EXHIBIT 10.3


                                  June 14, 1999

Unisys Corporation
Unisys Way
Blue Bell, Pennsylvania  19424

PulsePoint Communications
6307 Carpinteria Avenue
Carpinteria, California  93013

Ladies and Gentlemen:

      The  undersigned  gives this letter in connection with the proposed merger
(the   "Merger")  of  PulsePoint   Communications,   a  California   corporation
("PulsePoint") with and into a wholly-owned subsidiary of Unisys Corporation,  a
Delaware  corporation  ("Unisys").  As an  inducement  and  condition to Unisys'
willingness  to enter  into the  Agreement  and Plan of Merger  between  Unisys,
PulsePoint and Shellco Inc. (the "Merger Agreement"), the undersigned gives this
letter agreement in favor of Unisys and PulsePoint.

      1. The undersigned  agrees,  subject to the satisfaction of the conditions
set forth in paragraph 2 hereof and upon receipt of written notice  delivered to
the  undersigned  at the  address  set forth below (by  facsimile  or  overnight
courier) to the effect that such  conditions  have been  satisfied,  to promptly
convert that  percentage  of its  holdings of  PulsePoint  Series B  Convertible
Preferred  Stock,  no par value  (the  "Preferred  Stock")  that is equal to the
lesser of (i) the  percentage  of  Preferred  Stock held by the Oak Entities (as
such term is defined below) agreed to be converted by the Oak Entities  pursuant
to a  substantially  identical  letter  agreement dated as of the date hereof or
(ii) thirty-seven percent (37%), such conversion to occur in accordance with the
terms of the Certificate of Determination of Rights, Preferences, Privileges and
Restrictions  of  Series  B  Convertible  Preferred  Stock  of  PulsePoint  (the
"Certificate  of  Determination")  prior to the record date (the "Record  Date")
established  for the special  meeting of  PulsePoint  shareholders  at which the
Merger will be considered (the "Special Meeting").

      2. The  obligations  of the  undersigned  set forth in  paragraph 1 hereof
shall be conditioned  upon the  satisfaction  or waiver of each of the following
conditions  precedent:  (1) the  registration  statement  containing  the  Proxy
Statement/Prospectus to be prepared with respect to the Special Meeting will, in
the reasonable  judgment of PulsePoint and Unisys,  be declared  effective (such
date, the  "Effective  Date") by the  Securities  and Exchange  Commission  (the
"SEC") on or before July 30, 1999, and (2) the registration statement containing
such  Proxy  Statement/Prospectus  identifies  a proposed  closing  date for the
Merger to occur on or before  August 31,  1999,  and such  Merger is  reasonably
expected to be consummated on or before such date.

      3. Unless otherwise agreed by the undersigned,  Unisys and PulsePoint,  if
the Effective  Date occurs or will occur on or before July 30, 1999,  the Record
Date shall be no later  than July 30,  1999 and will not,  in any case,  be more
than seven (7)  calendar  days prior to the date agreed upon by  PulsePoint  and
Unisys as the likely date on which the  registration  statement  containing  the
Proxy  Statement/Prospectus  will be declared effective by the SEC. In the event
that the Effective  Date is later than July 30, 1999, the  undersigned  shall no
longer be required to convert its shares of Preferred  Stock and the Record Date
may be a date later than July 30, 1999.

      4. The undersigned has been informed that each of Oak Investment  Partners
V, Limited Partnership;  Oak Investment Partners VII, Limited  Partnership;  Oak
Investment Partners III, A Limited Partnership; Oak VII Affiliates Fund, Limited
Partnership;  Oak V  Affiliates  Fund,  Limited  Partnership;  Bandel L.  Carano
(collectively, the "Oak Entities"); Citiventure 96 Partnership, L.P.; Chancellor
Private Capital Offshore Partners II, L.P.;  Chancellor Private Capital Partners
III, L.P.;  Chancellor  Private  Capital  Offshore  Partners I, C.V.;  Microsoft
Corporation and Frederick J. Warren have executed a letter agreement  similar to
that given hereto and gives this letter agreement in reliance thereon.


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Unisys Corporation
PulsePoint Communications
June 14, 1999
Page 2


      5. The  shares of  PulsePoint  Common  Stock,  no par value  (the  "Common
Stock") received upon conversion of the shares of Preferred Stock shall continue
to be subject to the terms of the Voting  Agreement  dated as of the date hereof
by and between Unisys and the undersigned (the "Voting Agreement").

      6. This letter  agreement shall be governed by and construed in accordance
with the laws of the  State  of  Delaware  regardless  of the  laws  that  might
otherwise govern under applicable principals of conflict of laws. The provisions
of Section 5.12 of the Voting Agreement shall apply to this letter agreement.

      7. The undersigned agrees that irreparable damage would occur in the event
that any of the  provisions  of this  letter  agreement  were not  performed  in
accordance with its specified terms or were otherwise breached.  The undersigned
accordingly agrees that Unisys and PulsePoint shall be entitled to an injunction
or  injunctions  to prevent  breaches of this letter  agreement  and to specific
performance of the terms and  provisions  hereof in addition to any other remedy
to which they are entitled at law or in equity.

                                    By:_________________________
                                    Name:_______________________
                                    Title:______________________

                                    Address for notices:


                                    ____________________________
                                    ____________________________
                                    ____________________________
                                    Attn: ______________________
                                    Telephone:  ________________
                                    Facsimile:  ________________

ACKNOWLEDGED AND AGREED TO BY:

UNISYS CORPORATION, a Delaware
corporation

By:___________________________
Name:_________________________
Title:________________________

PULSEPOINT COMMUNICATIONS,
a California corporation

By:___________________________
Name:_________________________
Title:________________________



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