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                                                                    EXHIBIT 10.7

                                                                  Execution Copy

                     WARRANTS REGISTRATION RIGHTS AGREEMENT


               WARRANTS REGISTRATION RIGHTS AGREEMENT, dated as of March 10,
2000 (this "Agreement"), between COLO.COM, a California corporation (the
"Company"), and STATE STREET BANK AND TRUST COMPANY OF CALIFORNIA, N.A., as
warrant agent (the "Warrant Agent").

               Pursuant to the terms of a Purchase Agreement, dated the date
hereof (the "Purchase Agreement"), among the Company, Goldman Sachs & Co., Bear,
Stearns & Co., Chase Securities Inc., Deutsche Bank Securities Inc., Warburg
Dillon Read LLC and Jefferies and Company, Inc. (the "Purchasers"), the Company
has agreed to issue and sell to the Purchasers an aggregate of 300,000 Warrants
(each, a "Warrant"), each Warrant initially entitling the holder thereof to
purchase 19.9718 Common Shares (as defined below) of the Company at a per share
exercise price equal to $0.01, as part of the issuance of 300,000 Units (the
"Units"), each consisting of one 13 7/8% Senior Note due 2010 of the Company
with a principal amount of $1,000 (each, a "Note" and collectively, the "Notes")
to be issued pursuant to the provisions of a Indenture to be dated as of the
Closing Date (the "Indenture") between the Company, as issuer, and State Street
Bank and Trust Company of California, N.A., as trustee, and one Warrant. The
Note and the Warrant included in each Unit will become separately transferable
at the close of business upon the earliest to occur of (i) the date that is one
year after the Closing Date (as defined below), (ii) 180 days after the closing
date of the Company's initial public offering, (iii) the commencement of an
exchange offer with respect to the Notes undertaken pursuant to the Registration
Rights Agreement (as defined below), (iv) the effectiveness of a shelf
registration statement with respect to resales of the Notes, (v) the
commencement of an offer to purchase the Notes upon a change of control and (vi)
such date as determined by Goldman, Sachs & Co. in its sole discretion.

               In consideration of the foregoing and of the mutual agreements
contained herein and in the Purchase Agreement, the Company and the Warrant
Agents hereby agree as follows:

               1.     Definitions.

               As used in this Agreement, the following capitalized defined
terms shall have the following meanings:

               "Auditors" means, at any time, the independent auditors of the
Company at such time.

               "Board" means the board of directors of the Company from time to
time.

               "Closing Date" means the date of issuance of the Units.



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               "Comfort Letter" has the meaning specified in Section 3 hereof.

               "Commission" means the United States Securities and Exchange
Commission.

               "Common Shares" means the shares of common stock, $0.01 par value
per share, of the Company and any other capital stock of the Company into which
such Common Shares may be converted or reclassified or that may be issued in
respect of, in exchange for or in substitution of such Common Shares by reason
of any stock splits, stock dividends, distributions, mergers, consolidations or
other like events.

               "Company" has the meaning specified in the preamble to this
Agreement.

               "Company Shares" has the meaning specified in Section 2(b)
hereof.

               "Cutback Notice" has the meaning specified in Section 2(a)
hereof.

               "Effectiveness Period" has the meaning specified in Section 3
hereof.

               "Exchange Act" has the meaning specified in Section 4 hereof.

               "Existing Registration Rights Agreement" means any registration
rights or similar agreement described in the Final Offering Memorandum under the
caption "Description of Capital Stock--Registration Rights", as it may be
amended, waived, supplemented, modified, restated, renewed or extended from time
to time, including any amendment, waiver supplement, modification, restatement,
renewal or extension entered into after the date hereof to include any shares
issuable after the date hereof in such agreement.

               "Existing Registration Rights Agreement Shares" has the meaning
specified in Section 2(b) hereof.

               "Expiration Date" means the tenth anniversary of the Closing
Date.

               "Holders" means the record holders of the Warrants and the
holders of Common Shares (or other securities) received upon exercise thereof.

               "Includible Secondary Shares" has the meaning specified in
Section 2(c) hereof.

               "Includible Shares" has the meaning specified in Section 2(b)
hereof.

               "Indemnified Person" has the meaning specified in Section 7(a)
hereof.

               "Indenture" has the meaning specified in the recitals to this
Agreement.



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               "managing underwriter" has the meaning specified in Section 2
hereof.

               "Notes" has the meaning specified in the recitals to this
Agreement.

               "Opinion" has the meaning specified in Section 3 hereof.

               "Other Shares" has the meaning specified in Section 2(b) hereof.

               "Person" means an individual, general partnership, limited
partnership, corporation, trust, joint stock company, association, joint venture
or any other entity or organization, whether or not legal entities, including,
without limitation, a government or political subdivision or an agency or
instrumentality thereof.

               "Piggy-back Registration Rights" has the meaning specified in
Section 2(a) hereof.

               "Purchasers" has the meaning specified in the recitals to this
Agreement.

               "Purchase Agreement" has the meaning specified in the recitals to
this Agreement.

               "Registration Rights Agreement" means the Registration Statement
dated as of the Closing Date between the Company and Goldman, Sachs & Co. for
itself and on behalf of the purchasers set forth in Schedule I of the Purchase
Agreement.

               "Registration Statement" has the meaning specified in Section
2(a) hereof.

               "Resale Shelf" has the meaning specified in Section 3 hereof.

               "Securities Act" means the United States Securities Act of 1933,
as amended.

               "Units" has the meaning specified in the recitals to this
Agreement.

               "Warrant" has the meaning specified in the recitals to this
Agreement.

               "Warrant Agent" has the meaning specified in the preamble to this
Agreement.

               "Warrant Agreement" means the Warrant Agreement dated as of the
Closing Date between the Company and State Street Bank and Trust Company of
California, N.A., relating to the Warrants.

               "Warrant Shares" means the Common Shares (or other securities)
issued or purchasable upon exercise of the Warrants.



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               "Warrant Shelf Registration Statement" has the meaning specified
in Section 3 hereof.


               2.     Piggy-Back Registration Rights.

               (a) If, prior to the date that is ten days prior to the
expiration of the Warrants, the Company proposes to file a Registration
Statement with the Commission respecting an offering of any Common Shares (or
other securities) purchasable upon exercise of the Warrants (other than (x) an
offering that could be registered solely on Form S-4, S-8, or F-4 or any
successor form thereto, (y) securities offered or issued pursuant to any
employment or benefit plan or arrangement to any employee, director, partner,
trustee or consultant or advisor of or to the Company or any subsidiary of the
Company, and (z) the initial public offering of Common Shares (or other
securities) purchasable upon exercise of the Warrants if no shareholder of the
Company participates therein as a selling shareholder), the Company shall give
prompt written notice to all the Holders of Warrants or Warrant Shares at least
30 days prior to the initial filing of the registration statement relating to
such offering (the "Registration Statement"). Each such Holder shall have the
right, within 20 days after delivery of such notice, to request in writing that
the Company include all or a portion of such of the Warrant Shares in such
Registration Statement ("Piggy-back Registration Rights"). The Company shall
include in the public offering all of the Warrant Shares that a Holder has
requested be included, unless the underwriter for the public offering or the
underwriter managing the public offering (in either case, the "managing
underwriter") delivers a notice (a "Cutback Notice") pursuant to Section 2(b) or
2(c) hereof. The managing underwriter may deliver one or more Cutback Notices at
any time prior to the execution of the underwriting agreement for the public
offering.

               (b) If a proposed public offering includes both securities to be
offered for the account of the Company ("Company Shares") and shares to be sold
by shareholders, the provisions of this Section 2(b) shall be applicable if the
managing underwriter delivers a Cutback Notice stating that, in its opinion, the
number of Common Shares that selling shareholders propose to sell therein (other
than shareholders proposing to sell shares pursuant to the registration rights
granted under the Existing Registration Rights Agreement (the "Existing
Registration Rights Agreement Shares")), whether or not such selling
shareholders have the right to include shares therein (the "Other Shares"), plus
the number of Warrant Shares that the Holders have requested to be sold therein,
plus the number of Existing Registration Rights Agreement Shares that the
holders thereof have requested to be sold therein, plus the Company Shares,
exceeds the maximum number of shares specified by the managing underwriter in
such Cutback Notice that may be distributed without materially and adversely
affecting the price, timing or distribution of the Company Shares. Such maximum
number of shares that may be so sold, excluding the Company Shares, are referred
to as the "Includible Shares."



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               If the managing underwriter delivers such Cutback Notice, the
Company shall be entitled to include all of the Company Shares in the public
offering and each requesting party (or beneficiary) exercising its registration
rights (or privileges) under the Existing Registration Rights Agreement, shall
be entitled to include in the public offering up to its pro rata portion of the
Includible Shares and in priority to the inclusion of any Warrant Shares and any
Other Shares that are proposed to be sold in such public offering, and each
requesting Holder shall be entitled to include in the public offering up to its
pro rata portion of the Includible Shares and in priority to the inclusion of
any Other Shares that are proposed to be sold in such public offering. No
shareholder that proposes to sell Other Shares in the proposed initial public
offering, other than as specified above, may sell any such shares therein unless
all Warrant Shares requested by the Holders to be sold therein are so included.

               (c) If a proposed public offering is entirely a secondary
offering, the provisions of this Section 2(c) shall be applicable if the
managing underwriter delivers a Cutback Notice stating that, in its opinion, the
aggregate number of Warrant Shares and Other Shares proposed to be sold therein
exceeds the maximum number of shares (the "Includible Secondary Shares")
specified by the managing underwriter in such Cutback Notice that may be
distributed without materially and adversely affecting the price, timing or
distribution of the Common Shares being distributed.

               (i) If the managing underwriter delivers such Cutback Notice, in
        the case of a demand registration pursuant to the Existing Registration
        Rights Agreement, first each party entitled to be included in such
        demand registration pursuant to the Existing Registration Rights
        Agreement shall be entitled to include all of its Includible Secondary
        Shares, and second each requesting Holder shall be entitled to include
        up to its pro rata portion of the remaining Includible Secondary Shares
        and in priority to the inclusion of any Other Shares, other than as
        specified above, that are proposed to be sold in such public offering;
        and

               (ii) If the managing underwriter delivers such Cutback Notice in
        the case of any other demand registration, first each party exercising
        such demand registration rights shall be entitled to include all of its
        Includible Secondary Shares, then each party entitled to be included in
        such demand registration pursuant to the Existing Registration Rights
        Agreement, and then each requesting Holder, shall be entitled to include
        up to its pro rata portion of the remaining Includible Secondary Shares
        and in priority to the inclusion of any Other Shares, other than as
        specified above, that are proposed to be sold in such public offering.

No shareholder that proposes to sell Other Shares in the proposed public
offering, other than as specified above, may sell any such shares therein unless
all Warrant Shares requested by the Holders to be sold therein are so included.



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               (d) The underwriting agreement for such public offering shall
provide that each requesting Holder shall have the right to sell its Warrant
Shares to the underwriters and that the underwriters shall purchase the Warrant
Shares at the price paid by the underwriters for the Common Shares sold by the
Company and/or selling shareholders, as the case may be.

               3. Shelf Registration. (a) If only the Company sells Common
Shares in an initial public offering or all of the Warrant Shares (or other
securities) purchasable upon exercise of the Warrants have not been sold in one
or more public offerings, the Company shall use its best efforts to cause to be
filed pursuant to Rule 415 under the Securities Act a shelf registration
statement on the appropriate form (the "Warrant Shelf Registration Statement")
covering the resale of the Warrant Shares (or other securities) by the Holders
and shall use its best efforts to cause the Warrant Shelf Registration Statement
to become effective under the Securities Act upon the earliest to occur (i) 180
days after the closing date of the initial public offering of the Company and
(ii) one year after the Closing Date (subject to an extension (not to exceed 90
days) if the Company is subject to a "lockup" or "blackout" period imposed
pursuant to or in connection with any underwriting or purchase agreement
relating to an underwritten Rule 144A or registered public offering of Common
Shares or securities convertible into or exchangeable for Common Shares). The
Company shall use reasonable efforts to keep the Warrant Shelf Registration
Statement continuously effective, subject to Section 4 hereof, until the earlier
of such time as all of the Warrants Shares have been resold and two years after
the Closing Date (the "Effectiveness Period"). Prior to filing the Warrant Shelf
Registration Statement or any amendment thereto, the Company shall provide a
copy thereof to Goldman, Sachs & Co. and its counsel and afford them a
reasonable time to comment thereon.

               (b) If the Warrant Shelf Registration Statement shall register
the resale of the Warrant Shares (a "Resale Shelf") as provided in Section 3(a)
above, the Company agrees to:

               (i) make available for inspection by a representative of the
        Holders, the managing underwriter participating in any disposition
        pursuant to such Resale Shelf and one firm of attorneys designated by
        the Holders (upon execution of customary confidentiality agreements
        reasonably satisfactory to the Company and its counsel), at reasonable
        times and in a reasonable manner, financial and other records, documents
        and properties of the Company that are pertinent to the conduct of due
        diligence customary for an underwritten offering, and cause the
        officers, directors and employees of the Company to supply all
        information reasonably requested by any such representative, underwriter
        or attorney in connection with a Resale Shelf as shall be necessary to
        enable such persons to conduct a reasonable investigation within the
        meaning of Section 11 of the Securities Act of 1933, as amended from
        time to time;

               (ii) use its reasonable best efforts to cause all Warrant Shares
        sold under a Resale Shelf to be listed on any securities exchange or any
        automated quotation system



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        on which similar securities issued by the Company are then listed, to
        the extent such Warrant Shares satisfy applicable listing requirements;

               (iii) provide a reasonable number of copies of the prospectus
        included in such Resale Shelf to Holders that are selling Warrant Shares
        pursuant to such Resale Shelf;

               (iv) if any disposition pursuant to such Resale Shelf is an
        underwritten offering, use its reasonable best efforts to cause to be
        provided to the managing underwriter upon the effectiveness of such
        Resale Shelf, a customary "10b-5" opinion of independent counsel (an
        "Opinion") and a customary "cold comfort" letter of independent auditors
        (a "Comfort Letter");

               (v) if any disposition pursuant to such Resale Shelf is an
        underwritten offering, use its reasonable best efforts to cause to be
        provided to the managing underwriter an Opinion and Comfort Letter with
        respect to each document, including any amendments thereto, that is
        incorporated by reference in such Resale Shelf; and

               (vi) notify the Warrant Agent and any managing underwriter in
        writing, for distribution to the Holders, (A) when the Resale Shelf has
        become effective and when any post-effective amendment thereto has been
        filed and becomes effective, (B) of any request by the Commission or any
        state securities authority for amendments and supplements to the Resale
        Shelf or of any material request by the Commission or any state
        securities authority for additional information after the Resale Shelf
        has become effective, (C) of the issuance by the Commission or any state
        securities authority of any stop order suspending the effectiveness of
        the Resale Shelf or the initiation of any proceedings for that purpose,
        (D) if, between the effective date of the Resale Shelf and the closing
        of any sale of Warrant Shares covered thereby, the representations and
        warranties of the Company contained in any underwriting agreement,
        securities sales agreement or other similar agreement, including this
        Agreement, relating to disclosure cease to be true and correct in all
        material respects or if the Company receives any notification with
        respect to the suspension of the qualification of the Warrant Shares for
        sale in any jurisdiction or the initiation of any proceeding for such
        purpose, (E) of the happening of any event during the period the Resale
        Shelf is effective such that such Resale Shelf or the related prospectus
        contains an untrue statement of a material fact or omits to state a
        material fact required to be stated therein or necessary to make
        statements therein not misleading (in the case of a prospectus, in light
        of circumstances under which they were made) and (F) of any
        determination by the Company that a post-effective amendment to a
        Registration Statement would be appropriate. The Holders hereby agree to
        suspend, and to cause any managing underwriter to suspend, use of the
        prospectus contained in a Resale Shelf upon receipt of such notice under
        clause (C), (E) or (F) above until, in the case of clause (C), such stop
        order is removed or rescinded or, in the case of



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        clauses (E) and (F), the Company has amended or supplemented such
        prospectus to correct such misstatement or omission or otherwise.

               (c) Each beneficial owner of Warrant Shares sold pursuant to a
Resale Shelf, by accepting its beneficial ownership of a Warrant or the Warrant
Shares, hereby (i) agrees to provide the Company with information with respect
to it that the Company reasonably requests in connection with any Resale Shelf.

               4.     Suspension.

               Notwithstanding the foregoing, during any consecutive 365-day
period while the Warrants are exercisable, the Company shall have the ability to
suspend the filing, effectiveness or use of such Warrant Shelf Registration
Statement for up to two 30-consecutive-day periods (except during the 30 days
immediately prior to the expiration of the Warrants) if:

               (a) an event or circumstance occurs and is continuing as a result
        of which the registration statement, any related prospectus or any
        document incorporated therein by reference, as then amended or
        supplemented or proposed to be filed, would, in the good faith
        determination of the Board, contain an untrue statement of a material
        fact or omit to state a material fact necessary in order to make the
        statements therein, in light of the circumstances under which they were
        made, not misleading; and

               (b) (i) the Board determines in good faith that the disclosure of
        such an event at such time would have a material adverse effect on the
        business, operations or prospects of the Company or (ii) the disclosure
        otherwise relates to a material business transaction which has not yet
        been publicly disclosed;

provided that the Effectiveness Period shall be extended by the number of days
in any such suspension period. The Company shall provide notice of such
determination to the Holders at their addresses appearing in the register of
Warrants maintained by the Warrant Agent.

               5.     Blue Sky.

               The Company shall use its reasonable best efforts to register or
qualify the Warrant Shares proposed to be sold or issued pursuant to the
Registration Statement or the Warrant Shelf Registration Statement under all
applicable securities or "blue sky" laws of all jurisdictions in the United
States in which any Holder of Warrants may or may be deemed to purchase Warrant
Shares upon the exercise of Warrants or resale of the Warrant Shares, as the
case may be, and shall use its reasonable best efforts to maintain such
registration or qualification through the earlier of (A) the date upon all
Warrant Shares have been resold under the Warrant Shelf Registration Statement
and (B) the Expiration Date; provided, however, that the Company shall not be
required to (i) qualify as a foreign corporation or as a broker or a dealer in
securities



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        in any jurisdiction where it would not otherwise be required to qualify
        but for this Section 5, (ii) file any general consent to service of
        process or (iii) subject itself to taxation in any jurisdiction if it is
        not otherwise so subject.

               6.     Accuracy of Disclosure.

               The Company (and its successors) represents and warrants to each
Holder (and each beneficial owner of a Warrant or Warrant Share) and agrees for
the benefit of each Holder (and each beneficial owner of a Warrant or Warrant
Share) that, except during any period in which the availability of the Warrant
Shelf Registration Statement has been suspended, (i) the Warrant Shelf
Registration Statement and the documents incorporated by reference therein will
not contain any untrue statement of a material fact or omit to state a material
fact necessary to make the statements therein not misleading; and (ii) the
prospectus delivered pursuant to which such Holder sells its Warrant Shares and
the documents incorporated by reference therein will not contain any untrue
statement of a material fact or omit to state a material fact necessary to make
the statements therein, in light of the circumstances under which they were
made, not misleading; provided, however, that representations, warranties and
agreements set forth in this Section 6 do not apply to statements or omissions
in the Warrant Shelf Registration Statement or any such prospectus based upon
information relating to any Holder furnished to the Company (or its successors)
in writing by such Holder expressly for use therein.

               7. Indemnity. (a) The Company hereby agrees to indemnify each
beneficial owner of a Warrant and each person, if any, who controls any
beneficial owner of a Warrant within the meaning of either Section 15 of the
Securities Act or Section 20 of the Securities Exchange Act of 1934, as amended
(the "Exchange Act"), or is under common control with, or is controlled by, any
beneficial owner of a Warrant (whether or not it is, at the time the indemnity
provided for in this Section 7 is sought, such a beneficial owner), from and
against all losses, damages or liabilities which such beneficial owner or any
such controlling or affiliated person ("Indemnified Person") suffers as a result
of any breach, on the date of the resale of any Warrant Share by such
Indemnified Person pursuant to the Warrant Shelf Registration Statement, of the
representations, warranties or agreements contained in Section 6. In addition,
the foregoing indemnity with respect to any preliminary Prospectus shall not
inure to the benefit of any Indemnified Person to the extent that any such
losses, claims, damages or liabilities result from the fact that such
Indemnified Person sold securities to a person to whom there was not sent or
given by or on behalf of such Indemnified Person (if required by law so to have
been delivered) a copy of the Prospectus (as then amended or supplemented if the
Company shall have furnished any amendments or supplements thereto) at or prior
to the written confirmation of the sale of the Warrant Shares to such person,
and if the losses, claims, damages or liabilities result from an untrue
statement or alleged untrue statement or an omission or alleged omission
contained in such preliminary Prospectus that was corrected in the Prospectus
(as so amended or supplemented), unless such failure is the result of
noncompliance by the Company with its obligations to deliver copies of the
Prospectus to the Indemnified Person, nor shall this indemnity



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agreement inure to the benefit of any Indemnified Person from whom the person
asserting any such losses, claims, damages or liabilities purchased the Warrant
Shares concerned to the extent that at the time of such purchase such
Indemnified Person had received written notice from the Company that the use of
such Prospectus, amendment, supplement or preliminary Prospectus was suspended
as provided in Section 3(b)(vi) or Section 4. In addition, the Company shall not
be liable in any such case to the extent that any such loss, damage or liability
arises out of or is based upon any untrue statement or alleged untrue statement
or omission or alleged omission made in any preliminary Prospectus or Prospectus
or any such amendment or supplement in reliance upon and in conformity with
written information furnished to the Company by any such Indemnified Person
expressly for use therein.

               (b) Promptly after receipt by an Indemnified Person under this
Section 7 of notice of the commencement of any action (including any
governmental action), such Indemnified Person will, if a claim in respect
thereof is to be made against any indemnifying party under this Section 7,
deliver to the indemnifying party a written notice of the commencement thereof
and the indemnifying party shall have the right to participate in, and, to the
extent the indemnifying party so desires, jointly with any other indemnifying
party similarly noticed, to assume the defense thereof with counsel mutually
satisfactory to the parties; provided, however, that an Indemnified Person shall
have the right to retain its own counsel, with the fees and expenses to be paid
by the indemnifying party, if representation of such indemnified party by the
counsel retained by the Indemnifying Person would be inappropriate due to actual
or potential conflict of interests between such Indemnified Person and any other
party represented by such counsel in such proceeding. The failure to deliver
written notice to the indemnifying party within a reasonable time of the
commencement of any such action, if materially prejudicial to its ability to
defend such action, shall relieve such indemnifying party of any liability to
the Indemnified Person under this Section 7, but the omission so to deliver
written notice to the indemnifying party will not relieve it of any liability
that it may have to any Indemnified Person otherwise than under this Section 7.

               8.     Expenses.

               All expenses incident to the Company's performance of or
compliance with its obligations under this Agreement will be borne by the
Company, regardless of whether a Registration Statement or Warrant Shelf
Registration Statement becomes effective, including without limitation (i) all
Commission or National Association of Securities Dealers, Inc. registration and
filing fees, (ii) all reasonable fees and expenses incurred in connection with
compliance with state securities or "blue sky" laws, (iii) all reasonable
expenses of any persons incurred by or on behalf of the Company in preparing or
assisting in preparing, word processing, printing and distributing any
registration statement, any prospectus, any amendments or supplements thereto
and other documents relating to the performance of and compliance with this
Agreement, (iv) the reasonable fees (including legal fees and expenses) and
disbursements of the Warrant Agent, (v) the reasonable fees and disbursements of
counsel for the Company and



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               (vi) the fees and disbursements, if any, of the Auditors, but
excluding (x) the reasonable fees and disbursements of counsel retained by the
participating Holders and (y) the Holders' share of underwriting discounts and
commissions.

               9.     "Market Stand Off" Agreement.

               Each Holder hereby agrees that during the 180 day period
following the effective date of an initial public offering of Common Shares (or
other securities purchasable upon exercise of the Warrants), it shall not, to
the extent requested by the Company or the managing underwriter, sell or
otherwise transfer or dispose of (other than to donees who agree to be similarly
bound) any Common Shares of the Company held by it at any time during such
period except Common Shares included in such registration; provided, however,
that all directors of the Company party to or beneficiaries of, from time to
time, the Existing Registration Rights Agreement and, if required by the
managing underwriter, the Management Investors, Beneficial Investors and others
party thereto, or beneficiaries thereof, from time to time, enter into or are
bound by similar agreements.

               In order to enforce the foregoing covenant, the Company may
impose stop-transfer instructions with respect to the Warrant Shares until the
end of such period.

               10.    Miscellaneous.

               (a) No Inconsistent Agreements. The Company represents and the
Warrant Agent represents to the best of its knowledge to the other that it has
not entered into, and agrees that on or after the date of this Agreement it will
not enter into, any agreement which is inconsistent with the rights granted to
the Holders of Warrants or Warrant Shares in this Agreement or otherwise
conflicts with the provisions hereof. The Company represents that the rights
granted to the Holders hereunder do not in any way conflict with and are not
inconsistent with the rights granted to the holders of the Company's other
issued and outstanding securities under any agreements (after giving effect to
any waiver, consent, amendment, resolution or other instrument in full force and
effect on the date hereof).

               (b) Amendments and Waivers. The provisions of this Agreement,
including the provisions of this sentence, may not be amended, modified or
supplemented, and waivers or consents to departures from the provisions hereof
may not be given unless the Company and the Warrant Agent have obtained the
written consent of Holders of at least a majority of the outstanding Warrants
affected by such amendment, modification, supplement, waiver or consent;
provided that any amendment, modification or supplement to this Agreement which,
in the good faith opinion of the Board of Directors of the Company (and
evidenced by a resolution of such board), does not adversely affect any Holder,
shall not be subject to such requirement for written consent.



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               (c) Notices. All notices and other communications provided for or
permitted hereunder shall be made in writing by hand-delivery, registered
first-class mail, telex, telecopier, or any courier guaranteeing overnight
delivery (i) if to a Holder, at the most current address given by such Holder to
the Company by means of a notice given in accordance with the provisions of this
Section 10(c); (ii) if to the Company, initially at the Company's address set
forth in the Indenture and thereafter at such other address, notice of which is
given in accordance with the provisions of this Section 10(c); and (iii) if to
the Warrant Agent, initially at the Warrant Agent's address set forth in the
Warrant Agreement and thereafter at such other address, notice of which is given
in accordance with the provisions of this Section 10(c).

               All such notices and communications shall be deemed to have been
duly given: at the time delivered by hand, if personally delivered; five
business days after being deposited in the mail, postage prepaid, if mailed;
when answered back, if telexed; when receipt is acknowledged, if telecopied; and
on the next business day if timely delivered to an air courier guaranteeing
overnight delivery.

               (d) Successors and Assigns. This Agreement shall inure to the
benefit of and be binding upon the successors, assigns and transferees of each
of the parties, including, without limitation, subsequent Holders; provided that
nothing herein shall be deemed to permit any assignment, transfer or other
disposition of Warrants in violation of the terms of the Purchase Agreement or
the Warrant Agreement. If any transferee of any Holder shall acquire Warrants,
in any manner, whether by operation of law or otherwise, such Warrants shall be
held subject to all of the terms of this Agreement and the Warrant Agreement,
and by taking and holding such Warrants such person shall be conclusively deemed
to have agreed to be bound by and to perform all of the terms and provisions of
this Agreement or the Warrant Agreement and such person shall be entitled to
receive the benefits hereof.

               (e) Purchases and Sales of Warrants. The Company shall not, and
shall use its best efforts to cause its affiliates (as defined in Rule 405 under
the Securities Act) not to, purchase and then resell or otherwise transfer
(other than to the Company or any subsidiary thereof) any Warrants other than
Warrants acquired and cancelled.

               (f) Third Party Beneficiary. The Holders shall be third party
beneficiaries to the agreements made hereunder between the Company and the
Warrant Agents, and each Holder shall have the right to enforce such agreements
directly to the extent it deems such enforcement necessary or advisable to
protect its rights or the rights of Holders hereunder.

               (g) Counterparts. This Agreement may be executed in any number of
counterparts and by the parties hereto in separate counterparts, each of which
when so executed shall be deemed to be an original and all of which taken
together shall constitute one and the same agreement.



   13

                                       13

               (h) Headings. The headings in this Agreement are for convenience
of reference only and shall not limit or otherwise affect the meaning hereof.

               (i) Governing Law. This Agreement shall be governed by the laws
of the State of New York. The Warrant Agent, the Company and the Holders agree
to submit to the jurisdiction of the courts of the State of New York in any
action or proceeding arising out of or related to this Agreement or the
Warrants.
               (j) Severability. In the event that any one or more of the
provisions contained herein, or the application thereof in any circumstance, is
held invalid, illegal or unenforceable, the validity, legality and
enforceability of any such provision in every other respect and of the remaining
provisions contained herein shall not be affected or impaired thereby.



   14

               IN WITNESS WHEREOF, the parties have executed this Agreement as
of the date first written above.



                                            COLO.COM


                                            By /s/ CHARLES M. SKIBO
                                              ----------------------------------
                                            Name: Charles M. Skibo
                                               Title: President and Chief
                                                      Financial Officer



                                            STATE STREET BANK AND TRUST COMPANY
                                            OF CALIFORNIA, N.A.,
                                            as Warrant Agent


                                            By /s/ SCOTT C. EMMONS
                                              ----------------------------------
                                               Name: Scott C. Emmons
                                               Title: Vice President



   15

                                                                  Execution Copy




                     WARRANTS REGISTRATION RIGHTS AGREEMENT



                                     between



                                    COLO.COM



                                       and



            STATE STREET BANK AND TRUST COMPANY OF CALIFORNIA, N.A.,

                                as Warrant Agent




                           Dated as of March 10, 2000