Exhibit 10.7

                                   SUBLEASE

     THIS SUBLEASE (this "Sublease") is dated for reference purposes as of 
February 12, 1999, and is made by and between Concentric Network Corporation 
("Sublandlord"), and Imgis, Inc., dba "AdForce" ("Subtenant"). Sublandlord and 
Subtenant hereby agree as follows:

     1. RECITALS: This Sublease is made with reference to the fact that Spieker 
Properties, L. P., a California limited partnership, as landlord ("Master 
Landlord"), and Sublandlord, as tenant, are parties to that certain Lease dated 
February 22, 1998 (the "Master Lease"), with respect to approximately 41,151 
square feet of space (the "Premises"), in that certain building (the 
"Building") located at 10590 N. Tantau Avenue, Cupertino, California. A copy of 
the Master Lease is attached hereto as EXHIBIT A. Capitalized terms used and 
not defined herein shall have the meaning ascribed to them in the Master Lease.

     2. SUBLEASED PREMISES: Subject to the terms and conditions of this 
Sublease, Sublandlord hereby subleases to Subtenant, and Subtenant hereby 
subleases from Sublandlord, the entire Premises.

     3. TERM:

          A. TERM. The term (the "Term") of this Sublease shall be for the 
period commencing on April 15, 1999 (the "Commencement Date"), subject to 
Paragraph 3.C below, and ending on April 23, 2003, unless this Sublease is 
sooner terminated pursuant to its terms or the Master Lease is sooner 
terminated pursuant to its terms (the "Expiration Date").

          B. OPTION TO EXTEND. Subtenant shall have no options or rights to 
extend the Term of this Sublease or expand the Premises.

          C. EARLY OCCUPANCY. Within five (5) days following (i) full execution 
of this Sublease by Sublandlord and Subtenant (and Subtenant's payment to 
Sublandlord of the prepaid rent and Security Deposit) and (ii) receipt by 
Sublandlord of the Consent to Sublease Agreement (the "Consent to Sublease") 
for this Sublease executed by Master Landlord, then Sublandlord shall deliver 
possession of the Premises to Subtenant (the "Early Occupancy Start Date") 
and following such delivery, Subtenant shall have the right to occupy and use 
the Premises for the permitted use described in this Sublease from the Early 
Occupancy Start Date until the Commencement Date (the "Early Occupancy 
Period"), provided such occupancy shall be subject to Sublandlord's rights to 
use the Data Center (as hereinafter defined) as set forth in Paragraph 3.D 
below, and provided further that such early occupancy shall be subject to all 
of the terms and conditions of this Sublease, excluding only the obligation 
to pay Rent (as defined in Paragraph 4.A below). If Sublandlord fails to 
deliver possession of the Premises to Subtenant within ten (10) days 
following (i) full execution of this Sublease by Sublandlord and Subtenant 
(and Subtenant's payment to Sublandlord of the prepaid rent and Security 
Deposit) and (ii) receipt by Sublandlord of the Consent to Sublease for this 
Sublease executed by Master Landlord, then Subtenant shall have the right to 
terminate this Sublease, provided Subtenant delivers written notice of 
termination to Sublandlord within five (5) days thereafter. Following full 
execution of this Sublease by Sublandlord and Subtenant (and Subtenant's 
payment to Sublandlord of the prepaid rent and Security Deposit), Sublandlord 
shall use its reasonable efforts to obtain the Master Landlord's written 
consent to this Sublease.

          D. DATA CENTER ACCESS. The parties acknowledge that Sublandlord will 
be operating its business in the Data Center during the Early Occupancy Period. 
The Data Center shall be defined as that 



portion of the Premises outlined in EXHIBIT B attached hereto. Notwithstanding 
anything to the contrary in this Sublease, Sublandlord shall have access to and 
the exclusive control over and possession of the Data Center through February 
28, 1999. Sublandlord shall provide Subtenant, however, limited access to the 
Data Center beginning on the Early Occupancy Start Date for the sole purpose of 
installing its telephone and network cabling provided (i) such limited access 
shall be during business hours only and Subtenant shall at all times be 
accompanied by an authorized employee of Sublandlord, (ii) such limited access 
shall not interfere with Sublandlord's business operations in the Data Center 
and (iii) such limited access shall be subject to all of the terms and 
conditions of this Sublease, excluding only the obligation to pay Rent. After 
February 28, 1999, Subtenant shall have the right to occupy the Data Center for 
the permitted uses described in this Sublease; provided, however, that after 
February 28, 1999, Sublandlord (i) shall continue to have, during the remainder 
of the Early Occupancy Period, the exclusive use of ten (10) racks in the Data 
Center and shall have reasonable access to the Data Center at all times during 
the remainder of the Early Occupancy Period.

     4. RENT: 

          A. BASE RENT. Commencing on the Commencement Date and continuing each 
month throughout the Term of this Sublease, Subtenant shall pay to Sublandlord 
as base rent for the Premises monthly installments as follows ("Base Rent"):



                                                     Monthly Base Rent
                                                  
          -------------------------------------------------------------
          April 15, 1999 - April 30, 1999                $47,323.65
          -------------------------------------------------------------
          May 1, 1999 - April 30, 2000                   $98,433.19
          -------------------------------------------------------------
          May 1, 2000 - April 30, 2001                  $102,370.52
          -------------------------------------------------------------
          May 1, 2001 - April 30, 2002                  $106,465.34
          -------------------------------------------------------------
          May 1, 2002 - April 23, 2003                  $110,723.95


Base Rent and Additional Rent, as defined in Paragraph 4.B below, 
(collectively, hereinafter "Rent") shall be paid in advance at least two (2) 
days prior to the (1st) day of each month. Rent for any period during the Term 
hereof which is for less than one (1) month of the Term shall be a pro rata 
portion of the monthly installment based on a thirty (30) day month. Rent shall 
be payable without notice or demand and without any deduction, offset, or 
abatement, in lawful money of the United States of America. Rent shall be paid 
directly to Sublandlord at 1400 Parkmoor Avenue, San Jose, California 95126, 
Attention: Peter J. Bergeron, or such other address as may be designated in 
writing by Sublandlord.

      B. ADDITIONAL RENT. All monies other than Base Rent required to be paid 
by Subtenant under this Sublease, including, without limitation, all amounts 
payable by Sublandlord in connection with the Master Lease or the Premises 
(including, without limitation, all "Operating Expenses", "Estimated Operating 
Expenses" and "Operating Expense Adjustments" under Article 7 of the Master 
Lease) shall be deemed


                                      -2-


additional rent ("Additional Rent"). Subtenant and Sublandlord agree, as a 
material part of the consideration given by Subtenant to Sublandlord for this 
Sublease, Subtenant shall pay all costs, expenses, taxes, insurance, 
maintenance and other charges of every kind and nature arising under the Master 
Lease in connection with the Premises accruing after the Commencement Date, 
such that Sublandlord shall receive, as net consideration for this Sublease, 
full reimbursement thereof.

      C. PREPAYMENT OF RENT. Upon execution hereof by Subtenant, Subtenant 
shall pay to Sublandlord the sum of Forty-Seven Thousand Three Hundred 
Twenty-Three Dollars and 65/100 ($47,323.65), which shall constitute Base Rent 
for the period April 15, 1999 through April 30, 1999.

     5. SECURITY DEPOSIT: Upon execution hereof, Subtenant shall deposit with 
Sublandlord the sum of Ninety-Eight Thousand Four Hundred Thirty-Three Dollars 
and 19/100 ($98,433.19) (the "Security Deposit"), in cash, as security for the 
performance by Subtenant of the terms and conditions of this Sublease. If 
Subtenant fails to pay Rent or other charges due under this Sublease or 
otherwise defaults with respect to any provision of this Sublease, then 
Sublandlord, without prejudice to any other remedy provided in this Sublease or 
by law, may draw upon, use, apply or retain all or any portion of the Security 
Deposit for the payment of any Rent or other charge in default, for the payment 
of any other sum which Sublandlord has become obligated to pay by reason of 
Subtenant's default, or to compensate Sublandlord for any loss or damage which 
Sublandlord has suffered thereby. If Sublandlord so uses or applies all or any 
portion of the Security Deposit, then Subtenant, within ten (10) days after 
demand by Sublandlord therefor, shall deposit cash with Sublandlord in the 
amount required to restore the Security Deposit to the full amount stated 
above. Sublandlord may commingle the Security Deposit with its own funds and 
Subtenant shall not be entitled to interest on the Security Deposit. The 
Security Deposit is not an advance rental deposit or a measure of damages 
incurred by Sublandlord in case of Subtenant's default. Upon the expiration of 
this Sublease and Subtenant's vacation of the Premises, provided Subtenant is 
not in default under  the terms of this Sublease, Sublandlord shall return to 
Subtenant so much of the Security Deposit as has not been applied by 
Sublandlord pursuant to this Paragraph, or which is not otherwise required to 
cure Subtenant's defaults.

     6. HOLDOVER: Subtenant acknowledges that the Termination Date of the 
Master Lease is April 30, 2003 and that it is critical that Subtenant surrender 
the Premises on or before the Expiration Date in accordance with the terms of 
this  Sublease. Accordingly, Subtenant shall indemnify, defend and hold 
harmless Sublandlord from and against all losses, costs, claims, liabilities 
and damages resulting from Subtenant's failure to surrender the Premises on the 
Expiration Date in the condition required under the terms of this Sublease 
(including, without limitation, any liability or damages sustained by 
Sublandlord as a result of a holdover of the Master Premises by Sublandlord 
occasioned by the holdover of the Premises by Subtenant). In addition, 
Subtenant shall pay Sublandlord holdover rent equal to one hundred fifty 
percent (150%) of Base Rent plus any Additional Rent payable hereunder for any 
period from the Expiration Date through the date Subtenant surrenders the 
Premises in the condition required hereunder.

     7. CONDITION: Sublandlord warrants to Subtenant, for the period 
commencing on the Early Occupancy Start Date and expiring sixty (60) days 
following the Commencement Date (the "Warranty Period"), that the existing 
plumbing, electrical, fire protection, lighting and air conditioning and 
heating systems in the Premises are in working order and repair on the Early 
Occupancy Start Date, except for those items set forth on EXHIBIT C attached 
hereto and incorporated herein. If a non-compliance with said warranty arises 
during the Warranty Period, Sublandlord shall after receipt of written notice 
from Subtenant setting forth with specificity the nature and extent of such 
non-compliance, rectify the same at Sublandlord's expense. If Subtenant does 
not give Sublandlord written notice of a non-compliance with this warranty 


                                      -3-


during the Warranty Period, correction of that non-compliance shall be the 
obligation of Subtenant, at Subtenant's sole cost and expense. The parties 
acknowledge and agree that Subtenant is subleasing the Premises on an "AS IS" 
basis, and that, except as set forth in this Paragraph 7 above, Sublandlord 
has made no representations or warranties, express or implied, whatsoever, with 
respect to the Premises, including, without limitation, any representation or 
warranty as to the suitability of the Premises for Subtenant's intended use. 
Notwithstanding anything to the contrary in this Sublease or the Master Lease, 
the foregoing warranty shall not apply to (and Sublandlord shall have no 
obligation to correct or pay for) any non-compliance or any deficiency or 
damage to any of the systems in the Premises described in this Section 7 above 
which is caused by or arises out of any act or omission of Subtenant, or its 
agents, employees, contractors or invitees.

     8. REPAIRS: Subject to Paragraph 7 of this Sublease, Sublandlord shall 
have no obligation whatsoever to make or pay the cost of any alterations, 
improvements or repairs to the Premises, including, without limitation, any 
improvement or repair required to comply with any law, regulation, building 
code or ordinance (including the Americans with Disabilities Act of 1990, as 
may be amended). In addition, Sublandlord shall have no obligation to perform 
any repairs or any other obligation of Master Landlord required to be performed 
by Master Landlord under the terms of the Master Lease (including, without 
limitation, Master Landlord's obligations under Articles 7, 8, 10, 23 and 24 of 
the Master Lease and Master Landlord's obligation to comply with laws) and 
Subtenant shall look solely to Master Landlord for performance of said 
obligations. Sublandlord shall, however, request performance of the same in 
writing from Master Landlord promptly after being requested to do so by 
Subtenant, and shall use Sublandlord's reasonable efforts (not including the 
payment of money, the incurring of any liabilities, or the institution of legal 
proceedings) to obtain Master Landlord's performance. Subtenant expressly 
waives the provisions of Section 1932, subsection 1, and Sections 1941 and 1942 
of the Civil Code of California and all rights to make repairs at the expense 
of Sublandlord as provided in Section 1942 of said Civil Code.

     9. ASSIGNMENT AND SUBLETTING: In the event of any Transfer, including 
without limitation, a Transfer to a "Permitted Tenant Affiliate" (as defined by 
and meeting the criteria set forth in Section 21.C of the Master Lease, as 
incorporated herein, even if Sublandlord consents or is deemed to have 
consented to the Transfer, Subtenant shall still be required to obtain the 
consent of the Master Landlord to any such Transfer, including to a Permitted 
Tenant Affiliate. If Subtenant is a public company, any sale of Subtenant's 
capital stock through any national market system or public exchange shall not 
be deemed a Transfer under the terms of this Sublease; provided, however, that 
Subtenant hereby agrees that such a sale could constitute a Transfer under the 
Master Lease and therefore, Subtenant hereby agrees that it shall be required 
to obtain Master Landlord's prior written consent to any such Transfer, unless 
in the Consent to Sublease, Master Landlord expressly acknowledges that such a 
sale does not constitute a Transfer. Notwithstanding anything to the contrary 
in this Sublease, Sublandlord's approval of any transfer, including a 
"Permitted Tenant Affiliate", shall be subject to the Master Landlord's written 
approval and subject to the Master Landlord's right to terminate the Master 
Lease as set forth in Section 21.A of the Master Lease.

     10. USE:

         A. Subtenant may use the Premises for general office purposes only and 
for no other purpose whatsoever.

         B. Subtenant shall not use, store, keep, handle, manufacture, 
transport, release, discharge, emit or dispose of any Hazardous Materials in, 
on, under, about, to or from the Premises. Subtenant may


                                      -4-


handle, store, use and dispose of products containing small quantities of 
Hazardous Materials for "general office purposes" (such as toner for copies) to 
the extent customary and necessary for the Permitted Use of the Premises; 
provided that Subtenant shall always handle, store, use and dispose of any such 
Hazardous Materials in a safe and lawful manner and never allow such Hazardous 
Materials to contaminate the Premises, Building, or Project or surrounding land 
or environment. Sublandlord shall release Subtenant from and against all 
liabilities, losses, costs and expenses (including attorneys' and consultants' 
fees), demands, causes of action, claims or judgments arising out of the use, 
generation, storage, release or disposal of Hazardous Materials by Sublandlord 
or its agents, employees, contractors or invitees on or about the Premises.

         C.   Subtenant shall not do or permit anything to be done in or about
the Premises which would (i) injure the Premises; or (ii) vibrate, shake, 
overload, or impair the efficient operation of the Premises or the sprinkler 
systems, heating, ventilating or air conditioning equipment, or utilities 
systems located therein. Subtenant shall not store any materials, supplies, 
finished or unfinished products or articles of any nature outside of the 
Premises. Subtenant shall comply with all reasonable rules and regulations 
promulgated from time to time by Master Landlord.

         D.   Subject to Paragraph 3 of this Sublease, Sublandlord hereby 
consents to Subtenant's use of the Data Center, the diesel storage and 
emergency power system, and the fire suppression system all of which are 
located within the Premises in connection with its sublease of the Premises 
provided that Subtenant obtains Master Landlord's express written consent to 
such use.

     11. EFFECT OF CONVEYANCE: As used in this Sublease, the term "Sublandlord" 
means the holder of the Tenant's interest under the Master Lease. In the event 
of any assignment or transfer of the Tenant's interest under the Master Lease, 
which assignment or transfer may occur at any time during the Term hereof in 
Sublandlord's sole discretion, Sublandlord shall be and hereby is entirely 
relieved of all covenants and obligations of Sublandlord hereunder, and it 
shall be deemed and construed, without further agreement between the parties 
hereto, that any transferee has assumed and shall carry out all covenants and 
obligations thereafter to be performed by Sublandlord hereunder. Sublandlord 
may transfer and deliver any security of Subtenant to the transferee of the 
Tenant's interest under the Master Lease, and thereupon Sublandlord shall be 
discharged from any further liability with respect thereto.

     12. DELIVERY AND ACCEPTANCE: Sublandlord shall deliver the Premises in 
broom-clean condition. This Sublease shall not be void or voidable, nor shall 
Sublandlord be liable to Subtenant for any loss or damage, by reason of delays 
in the Commencement Date or delays in Sublandlord delivering the Premises to 
Subtenant for any reason whatsoever, except as expressly set forth in Paragraph 
3.C of this Sublease. Subtenant has fully inspected the Premises and is 
satisfied with the condition thereof. By taking possession of the Premises, 
Subtenant conclusively shall be deemed to have accepted the Premises in its 
then-existing, "AS IS" condition, without any representation or warranty 
whatsoever from Sublandlord with respect thereto, except as expressly set forth 
in Paragraph 7 of this Sublease.

      13. IMPROVEMENTS: Subtenant shall not make any alterations or 
improvements to the Premises, except in accordance with the Master Lease, and 
except with the prior written consent of both Master Landlord and Sublandlord.


                                      -5-


     14. DATA CENTER EQUIPMENT: On or before the Early Occupancy Start Date, 
Sublandlord shall execute and deliver a bill of sale conveying to Subtenant all 
of the items set forth on EXHIBIT D attached hereto.

     15. RELEASE AND WAIVER OF SUBROGATION: Notwithstanding anything to the 
contrary in this Sublease, Sublandlord and Subtenant hereby release each other 
(and Subtenant shall release Master Landlord) from any damage to property or 
loss of any kind which is caused by or results from any risk that is insured 
against under any property insurance policy required to be carried by either 
party or is actually carried by either party in connection with this Sublease. 
This release shall be in effect only so long as the applicable insurance policy 
contains a clause to the effect that this release shall not affect the right of 
the insured to recover under the policy. Each party shall use its reasonable 
efforts to cause each property insurance policy obtained by it to provide that 
the insurer waives all right of recovery against the other party and its agents 
and employees in connection with any damage or injury covered by the policy, 
and each party shall notify the other party if it is unable to obtain a waiver 
of subrogation. Sublandlord shall not be liable to Subtenant, nor shall 
Subtenant be entitled to terminate this Sublease or to abate Rent for any 
reason, including, without limitation, (i) failure or interruption of any 
utility system or service or (ii) failure of Master Landlord to maintain the 
Premises as may be required under the Master Lease. The obligations of 
Sublandlord and Subtenant shall not constitute the personal obligations of the 
officers, directors, trustees, partners, joint venturers, members, owners, 
stockholders or other principals or representatives of the business entity.

     16. INSURANCE: Subtenant shall obtain and keep in full force and effect, 
at Subtenant's sole cost and expense, during the Term the insurance required to 
be carried by the "Tenant" under the Master Lease. Subtenant shall include 
Sublandlord and Master Landlord as an additional insured in any policy of 
insurance carried by Subtenant in connection with this Sublease and shall 
provide Sublandlord with certificates of insurance upon the Early Occupancy 
Start Date.

     17. DEFAULT: Subtenant's failure to perform each of its obligations under 
this Sublease shall be deemed a material default under this Sublease. In 
addition, Subtenant shall be in material default of its obligations under this 
Sublease if Subtenant is responsible for the occurrence of any of the events of 
default set forth in Section 26 of the Master Lease, incorporated herein, as 
modified by this Sublease, or if Subtenant commits any other act or omission 
which constitutes a default under the Master Lease.

     18. SUBLANDLORD DEFAULT: Sublandlord shall not be deemed in default of 
this Sublease unless Sublandlord fails within a reasonable period of time to 
perform an obligation required to be performed by Sublandlord. For purposes of 
this Paragraph 18, a reasonable period of time shall in no event be less than 
thirty (30) days after receipt by Sublandlord of written notice specifying 
wherein such obligation of Sublandlord which has not been performed; provided, 
however, that if the nature of Sublandlord's obligation is such that more than 
thirty (30) days after such notice are reasonably required for its performance, 
then Sublandlord shall not be in default of this Sublease if performance is 
commenced within such thirty (30) day period and thereafter diligently pursued 
to completion.

     19. REMEDIES: In the event of any default by Subtenant, Sublandlord shall 
have all remedies provided to the "Landlord" in the Master Lease as if an event 
of default had occurred thereunder and all other rights and remedies otherwise 
available at law and in equity. Without limiting the generality of the 
foregoing, Landlord shall have the remedy described in California Civil Code 
Section 1951.4 (Sublandlord may continue the Sublease in effect after 
Subtenant's breach and abandonment and recover rent as it becomes


                                      -6-


due, if Subtenant has right to sublet or assign, subject only to reasonable 
limitations). Sublandlord may resort to its remedies cumulatively or in the 
alternative.

     20. SURRENDER: On or before the Expiration Date or any sooner termination 
of this Sublease, Subtenant shall remove all of its trade fixtures, personal 
property and all alterations constructed by Subtenant in the Premises which are 
required to be removed under the terms of this Sublease or the Master Lease and 
shall surrender the Premises to Sublandlord in (a) good condition, order and 
repair, reasonable wear and tear excepted and (b) free of Hazardous Materials 
used, stored, handled, manufactured, transported, released, discharged, emitted 
or disposed of by Subtenant or it agents, employees, contractors or invitees. 
Subtenant shall repair any damage to the Premises caused by Subtenant's removal 
of its personal property, furnishings and equipment. If the Premises are not so 
surrendered, then Subtenant shall be liable to Sublandlord for all reasonable 
costs incurred by Sublandlord in returning the Premises to said required 
condition, plus interest thereon at the Applicable Interest Rate. Subtenant 
shall not be required to remove any tenant improvements or alterations 
installed in the Premises by Sublandlord. Subtenant shall be required to remove 
all equipment set forth on EXHIBIT D, to the extent such removal is permitted 
under the terms of this Sublease and/or the Master Lease, of if required by 
Sublandlord.

     21. BROKER: Sublandlord and Subtenant each represent to the other that 
they have dealt with no real estate brokers, finders, agents or salesmen in 
connection with this transaction other than Spallino Reid representing 
Sublandlord and Cornish & Carey representing Subtenant. Each party agrees to 
indemnify and hold the other party harmless from and against all claims for 
brokerage commissions, finder's fees or other compensation made by any other 
agent, broker, salesman or finder as a consequence of the other party's actions 
or dealings with such other agent, broker, salesman, or finder.

     22. NOTICES: Unless at least five (5) days' prior written notice is given 
in the manner set forth in this paragraph, the address of each party for all 
purposes connected with this Sublease shall be that address set forth below 
their signatures at the end of this Sublease. All notices, demands or 
communications in connection with this Sublease shall be properly addressed and 
delivered as follows: (a) personally delivered; or (b) submitted to an 
overnight courier service, charges prepaid; or (c) deposited in the mail 
(certified, return-receipt requested, and postage prepaid). Notices shall be 
deemed delivered upon receipt, if personally delivered, one (1) business day 
after being so submitted to an overnight courier service and two (2) business 
days after deposit in the United States mail, if mailed as set forth above. All 
notices given to Master Landlord under the Master Lease shall be considered 
received only when delivered in accordance with the Master Lease.

     23. OTHER SUBLEASE TERMS:

         A. INCORPORATION BY REFERENCE. Except as set forth below and except as 
otherwise provided in this Sublease, the terms and conditions of this Sublease 
shall include all of the terms of the Master Lease and such terms are 
incorporated into this Sublease as if fully set forth herein, except that: (i) 
each reference in such incorporated sections to "Lease" shall be deemed a 
reference to this "Sublease"; (ii) each reference to the "Premises" shall be 
deemed a reference to the "Premises" herein; (iii) each reference to "Landlord" 
and "Tenant" shall be deemed a reference to "Sublandlord" and "Subtenant", 
respectively, except as otherwise expressly set forth herein; (iv) with respect 
to work, services, utilities, electricity, repairs (or damage caused by Master 
Landlord), restoration, insurance, indemnities, reimbursements, 
representations, warranties which are the obligation of the Master Landlord 
under the Master Lease or the performance of any other obligation of Master 
Landlord under the Master Lease, whether or not incorporated herein, the sole 


                                      -7-


obligation of Sublandlord shall be to request the same in writing from Master 
Landlord as and when requested to do so by Subtenant, and to use Sublandlord's 
reasonable efforts (not including the payment of money, the incurring of any 
liabilities, or the institution of legal proceedings) to obtain Master 
Landlord's performance; (v) with respect to any obligation of Subtenant to be 
performed under this Sublease, wherever the Master Lease grants to "Tenant" a 
specified number of days to perform its obligations under the Master Lease, 
except as otherwise provided herein, Subtenant shall three (3) fewer days (but 
not less than three (3)) to perform the obligation, including, without 
limitation, curing any defaults; (vi) with respect to any approval required to 
be obtained from the "Landlord" under the Master Lease, such approval must be 
obtained from both Master Landlord and Sublandlord, and Sublandlord's 
withholding of approval shall in all events be deemed reasonable if for any 
reason Master Landlord's approval is not obtained or is denied; (vii) with 
respect to any approval required to be obtained from the Sublandlord in 
connection with this Sublease, Sublandlord's approval shall not be unreasonably 
withheld, except to the extent otherwise set forth in the Master Lease, 
provided Sublandlord's withholding of approval shall in all events be deemed 
reasonable if for any reason Master Landlord's approval is not obtained or is 
denied; (viii) in any case where the "Landlord" reserves or is granted the 
right to manage, supervise, control, repair, alter, regulate the use of, enter 
or use the Premises or any areas beneath, above or adjacent thereto, such 
reservation or grant of right of entry shall be deemed to be for the benefit of 
both Master Landlord and Sublandlord; (viii) in any case where "Tenant" is to 
indemnify, release or waive claims against "Landlord", such indemnity, release 
or waiver shall be deemed to run from Subtenant to both Master Landlord and 
Sublandlord; (ix) in any case where "Tenant" is to execute and deliver certain 
documents or notices to "Landlord", such obligation shall be deemed to run from 
Subtenant to both Master Landlord and Sublandlord; and (x) the following 
modifications shall be made to the Master Lease as incorporated herein:

     (a) the following provisions of the Master Lease are not incorporated 
herein: Basic Lease Information (except Landlord and Landlord's Notice Address 
(for the purpose of incorporating the Master Landlord's name and address, only) 
and except for Project Description, Building Description, Permitted Use, 
Parking Density, Tenant's Proportionate Share of Building, Tenant's 
Proportionate Share of Project) Sections 3, 6, 19, 32 (first sentence), 
Additional Paragraphs to Lease Section 39 and the Addenda to Lease Agreement; 
references to "Landlord" in the following provisions shall mean "Master 
Landlord" only (subject, however, to clauses (iv) through (ix) of the 
introductory language to this Paragraph 22.A): Sections 7.E, 8.A, 10, 16, 20,
24 (except first reference to "Landlord" and except 24.E) and 28;

     (b) references to "twenty (20) days" in Section 7.E shall be changed to 
"fifteen (15) days";

     (c) the phrase "except as expressly otherwise provided in Paragraph 10" in 
the second sentence of Section 8.B(6) of the Lease shall be deleted;

     (d) Section 34 of the Lease, incorporated herein, shall not apply to 
Subtenant's obligation to surrender the Premises in accordance with the 
Sublease or apply to any monetary obligation of Subtenant;

     (e) any right to abate rent provided to Subtenant through incorporation of 
the provisions of the Master Lease shall not exceed the rent actually abated 
under the Master Lease.

     24. ASSUMPTION OF OBLIGATIONS: This Sublease is and at all times shall be 
subject and subordinate to the Master Lease and the rights of Master Landlord 
thereunder. Subtenant hereby expressly assumes and agrees: (i) to comply with 
all provisions of the Master Lease which are assumed by Subtenant hereunder; 
and (ii) to perform all the obligations on the part of the "Tenant" to be 
performed under the terms of the Master


                                      -8-


Lease, except as otherwise expressly provided herein. In the event the Master 
Lease is terminated for any reason whatsoever, this Sublease shall terminate 
simultaneously with such termination without any liability of Sublandlord to 
Subtenant. In the event of a conflict between the provisions of this Sublease 
and the Master Lease, as between Sublandlord and Subtenant, the provisions of 
this Sublease shall control.

     25. RIGHT TO CONTEST: If Sublandlord does not have the right to contest 
any matter in the Master Lease due to expiration of any time limit that may be 
set forth therein or for any other reason, then notwithstanding any 
incorporation of any such provision from the Master Lease in this Sublease, 
Subtenant shall also not have the right to contest any such matter.

     26. DAMAGE AND DESTRUCTION: Notwithstanding anything to the contrary in 
Section 24 of the Master Lease, as incorporated herein, in the event the 
Premises or the Building should be damaged or destroyed by a Casualty which is 
not due to an act or omission of Subtenant or its agents, employees, invitees 
or contractors, then Subtenant shall have the right to terminate this Sublease 
if material restoration of the Premises are not substantially completed within 
one hundred and eighty (180) days after the date of the damage or destruction.

     27. CONDITIONS PRECEDENT: Notwithstanding anything to the contrary in this 
Sublease, this Sublease and Sublandlord's and Subtenant's obligations hereunder 
are conditioned upon Sublandlord's receipt of the written consent of Master 
Landlord to this Sublease in form and substance satisfactory to Sublandlord and 
Subtenant. If Sublandlord does not receive such consent within thirty (30) days 
after execution of this Sublease by Sublandlord and Subtenant, then Sublandlord 
may terminate this Sublease by giving Subtenant written notice thereof prior 
to receipt of such consent, and upon such termination, Sub landlord shall 
return to Subtenant the first month's Base Rent paid by Subtenant pursuant to 
Paragraph 4.C hereof and the Security Deposit. If Sublandlord does not receive 
such consent within forty-five (45) days after full execution of this Sublease 
by Sublandlord and Subtenant, then Subtenant may terminate this Sublease by 
giving Sublandlord written notice thereof prior to receipt of such consent, and 
upon such termination, Sublandlord shall return to Subtenant the first month's 
Base Rent paid by Subtenant pursuant to Paragraph 4.C hereof and the Security 
Deposit. Subtenant can elect to waive the incorporation in the Consent to 
Sublease of the "Special Provisions" (described in Subtenant's insert 6 
"Special Provisions" to the Consent to Sublease), provided Subtenant delivers 
written notice to Sublandlord setting forth such waiver.

     28. SUBORDINATION, NON-DISTURBANCE AND ATTORNMENT AGREEMENT: Upon full 
execution of this Sublease by Sublandlord and Subtenant, Sublandlord shall ask 
Master Landlord to request that any lender of Master Landlord who has a 
security interest in the Premises or the Building, to provide Subtenant with a 
Subordination, Non-Disturbance and Attornment Agreement in connection with this 
Sublease. The execution or delivery of such an agreement shall not be a 
condition to this Sublease.

     29. MASTER LEASE: Sublandlord shall at all times faithfully and timely 
comply with all of its obligations under the Master Lease which have not been 
assumed by Subtenant under this Sublease. Without limiting any other right or 
remedy of Subtenant under this Sublease, if Master Landlord seeks to terminate 
the Master Lease because of an event of default by Sublandlord, Sublandlord 
shall use its reasonable good faith efforts to maintain the Master Lease in 
full force and effect for the benefit of Subtenant. To the actual knowledge of 
Sublandlord, without further inquiry: (a) the Master Lease is in full force and 
effect and there exists under the Master Lease no default or event of default 
by either Master Landlord or Sublandlord, nor has there occurred any event 
which with the giving of notice or the passage of time or both, could 
constitute such a default or event of default; (b) there are no pending or 
threatened actions, suits or proceedings before


                                      -9-


any court or administrative agency against Sublandlord which could adversely 
affect the Premises or any part thereof or the ability of Sublandlord to 
perform its obligations under the Master Lease; (c) there is no pending or 
threatened condemnation or similar proceeding affecting the Premises or any 
portion thereof, and Sublandlord has no knowledge that any such action 
currently is contemplated; (d) Sublandlord has not received any written notice 
from any insurance company of any defects or inadequacies of the Premises which 
would adversely affect the insurability of the Premises or materially increase 
the premiums for insurance thereof; and (e) Sublandlord has not received any 
written notice from any applicable governmental agency that the condition of 
the Premises violates any applicable law or regulation; and (f) there are no 
Hazardous Materials on the Premises that require remediation under any 
applicable environmental laws. If there is an Event of Default under the Master 
Lease which is due to an act or omission of Sublandlord (and not due to an act 
or omission of Subtenant or any of its agents, employees, contractors, 
invitees, successors, subtenants or assigns), Subtenant can elect, at is sole 
discretion, to cure such Event of Default by making payment directly to the 
Master Landlord or performing such obligation, and thereafter, until 
Sublandlord reimburses Subtenant for its out of pocket costs incurred for such 
direct performance (plus interest at the Applicable Interest Rate from the date 
paid by Subtenant until the dated reimbursed by Sublandlord), Subtenant can 
further elect to make all payments or other performances required hereunder 
directly to the Master Landlord, provided Master Landlord elects to recognize 
and/or permit such action. If there is an Event of Default under the Master 
Lease due to an act or omission of Subtenant or Subtenant's agents, employees, 
contractors, invitees, successors, subtenants or assigns, Subtenant shall not 
have the rights set forth in the immediately preceding sentence.

        30.  COUNTERPARTS: This Sublease may be executed in one (1) or more 
counterparts each of which shall be deemed an original but all of which 
together shall constitute one (1) and the same instrument. Signature copies may 
be detached from the counterparts and attached to a single copy of this 
Sublease physically to form one (1) document.

       IN WITNESS WHEREOF, the parties have executed this Sublease as of the 
day and year first above written.


SUBLANDLORD:                                 SUBTENANT:

CONCENTRIC NETWORK CORPORATION               IMGIS, INC. DBA "ADFORCE"

By: /s/ PETER J. BERGERON                    By: /s/ REX S. JACKSON
    ------------------------------               ----------------------------
Print Name: PETER J. BERGERON                Print Name: REX S. JACKSON
            ----------------------                       --------------------
Title: CORPORATE SECRETARY                   Title: V.P. & G.C.
       ---------------------------                  -------------------------

By:___________________________               By:_____________________________

Print Name:___________________               Print Name:_____________________

Title:________________________               Title:__________________________


Address:                                     Address:


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