<PAGE>

                                                                   EXHIBIT 10.12
--------------------------------------------------------------------------------




                            STOCK PURCHASE AGREEMENT

                                     among

                             NEWSUB SERVICES, INC.,

                      GENERAL ATLANTIC PARTNERS 49, L.P.,

                                      and

                        GAP COINVESTMENT PARTNERS, L.P.

                        ------------------------------

                         Dated as of September 9, 1998

                        ------------------------------



--------------------------------------------------------------------------------
<PAGE>

                               Table of Contents
                               -----------------


<TABLE>
<CAPTION>
                                                                    Page
                                                                    ----
<S>                                                                 <C>
ARTICLE 1  DEFINITIONS..............................................   1
      1.1  Definitions..............................................   1
      1.2  Accounting Terms; Financial Statements...................   6

ARTICLE 2  PURCHASE AND SALE OF PREFERRED STOCK.....................   6
      2.1  Purchase and Sale of Preferred Stock.....................   6
      2.2  Certificate of Designation...............................   6
      2.3  Closing..................................................   6

ARTICLE 3  REPRESENTATIONS AND WARRANTIES OF THE COMPANY............   7
      3.1  Corporate Existence and Power............................   7
      3.2  Authorization; No Contravention..........................   7
      3.3  Governmental Authorization; Third Party Consents.........   7
      3.4  Binding Effect...........................................   8
      3.5  Capitalization...........................................   8
      3.6  Financial Statements.....................................   9
      3.7  No Material Adverse Change; Ordinary Course of Business..   9
      3.8  Disclosure...............................................   9
      3.9  Private Offering.........................................   9
      3.10 No Default or Breach; Contractual Obligations............   9
      3.11 Broker's, Finder's or Similar Fees.......................  10

ARTICLE 4  REPRESENTATIONS AND WARRANTIES OF THE PURCHASERS.........  10
      4.1  Existence and Power......................................  10
      4.2  Authorization; No Contravention..........................  10
      4.3  Governmental Authorization; Third Party Consents.........  10
      4.4  Binding Effect...........................................  10
      4.5  Purchase for Own Account.................................  11
      4.6  Investment Experience....................................  12
      4.7  Broker's Finder's or Similar Fees........................  12

ARTICLE 5  CONDITIONS TO THE OBLIGATION OF THE PURCHASERS TO CLOSE..  12
      5.1  Secretary's Certificate..................................  12
      5.2  Stockholders Agreement Amendment.........................  12
      5.3  Registration Rights Agreement Amendment..................  13
      5.4  Purchased Shares.........................................  13
      5.5  Consents and Approvals...................................  13
      5.6  Amendment to Certificate of Incorporation................  13
      5.7  Revised Budget...........................................  13
      5.8  Credit Agreement Amendment...............................  13
</TABLE>

                                      -i-
<PAGE>

                               Table of Contents
                               -----------------
<TABLE>
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                                                                    ----
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ARTICLE 6  CONDITIONS TO THE OBLIGATION OF THE COMPANY TO CLOSE.....  14
      6.1  Payment by the Purchasers................................  14

ARTICLE 7  INDEMNIFICATION..........................................  14
      7.1  Indemnification by the Company...........................  14
      7.2  Indemnification by Purchasers............................  15
      7.3  Notification.............................................  15

ARTICLE 8  MISCELLANEOUS............................................  16
      8.1  Survival of Representations and Warranties...............  16
      8.2  Notices..................................................  17
      8.3  Successors and Assigns; Third Party Beneficiaries........  17
      8.4  Amendment and Waiver.....................................  17
      8.5  Counterparts.............................................  17
      8.6  Headings.................................................  18
      8.7  Pronouns.................................................  18
      8.8  GOVERNING LAW............................................  18
      8.9  Severability.............................................  18
      8.10 Entire Agreement.........................................  18
      8.11 Fees.....................................................  18
      8.12 Publicity................................................  18
      8.13 Further Assurances.......................................  19
</TABLE>

Exhibits

A.   Stockholders Agreement Amendment

B.   Registration Rights Agreement Amendment

Schedules

2.1  Purchase and Sale of Preferred Stock

3.5  Stock Ownership of NewSub Services, Inc.

8.2  Addresses

                                      -ii-
<PAGE>

                           STOCK PURCHASE AGREEMENT

          STOCK PURCHASE AGREEMENT, dated as of September 9, 1998 (this
"Agreement"), among NewSub Services, Inc., a Connecticut corporation (the
"Company"), General Atlantic Partners 49, L.P., a Delaware limited partnership
("GAP LP") and GAP Coinvestment Partners, L.P., a New York limited partnership
("GAP Coinvestment" and, together with GAP LP, the "Purchasers").

          WHEREAS, pursuant to the terms and conditions set forth in the Stock
Purchase Agreement, dated March 9, 1998, General Atlantic Partners 46, L.P.
("GAP 46"), a partnership related to the Purchasers, and GAP Coinvestment
purchased and now are the record and beneficial owners of the Company's common
stock in the following amounts (a) GAP 46 owns 117.18 shares of voting common
stock (the "Voting Stock") and 1,014 shares of nonvoting common stock (the
"Nonvoting Stock," and collectively with the Voting Stock, the "Common Stock"),
and (b) GAP Coinvestment owns 25.88 shares of Voting Stock and 223.94 shares of
Nonvoting Stock;

          WHEREAS, pursuant to the terms and conditions set forth in this
Agreement, the Company proposes to issue and sell to (a) GAP LP, for an
aggregate purchase price of $16,155,313, an aggregate of 568.15 shares of Series
A Convertible Preferred Stock, par value $.01 per share, of the Company (the
"Preferred Stock") and (b) GAP Co-investment, for an aggregate purchase price of
$3,844,687, an aggregate of 135.21 shares of Preferred Stock;

          WHEREAS, each share of Preferred Stock is convertible (subject to
adjustment) into one share of Voting Stock;

          NOW, THEREFORE, in consideration of the mutual covenants and
agreements set forth herein and for good and valuable consideration, the receipt
and adequacy of which is hereby acknowledged, the parties hereto agree as
follows:

                                   ARTICLE 1

                                  DEFINITIONS
                                  -----------

          1.1  Definitions.   As used in this Agreement, and unless the context
               -----------
requires a different meaning, the following terms have the meanings indicated:

          "Affiliate" shall mean any Person who is an "affiliate" as defined in
           ---------
Rule 12b-2 of the General Rules and Regulations under the Exchange Act. GAP LP,
GAP 46 and GAP Coinvestment shall be deemed to be Affiliates of one another.
<PAGE>

                                                                               2



          "Agreement" means this Agreement as the same may be amended
           ---------
supplemented or modified in accordance with the terms hereof.

          "Audited Financial Statements" means, with respect to a fiscal year,
           ----------------------------
the audited consolidated balance sheet of the Company as of the end of such
fiscal year and the related statements of operations, cash flows and
stockholders' equity for such fiscal year, setting forth in each case in
comparative form the figures for the previous year, all in conformity with GAAP,
in reasonable detail and accompanied by a management summary and analysis of the
operations of the Company for such fiscal year and by the opinion of a
nationally recognized independent certified public accounting firm reasonably
satisfactory to the Purchasers.

          "Board of Directors" means the Board of Directors of the Company.
           ------------------

          "Business Day" means any day other than a Saturday, Sunday or other
           ------------
day on which commercial banks in the State of New York are authorized or
required by law or executive order to close.

          "By-laws" means the by-laws of the Company in effect on the date
           -------
hereof, as the same may be amended from time to time.

          "Capital Lease Obligations" of any Person shall mean, as of the date
           -------------------------
of determination, the obligations of such Person to pay rent or other amounts
under any lease of (or other arrangement conveying the right to use) real or
personal property, or a combination thereof, which obligations are required to
be classified and accounted for as capital leases on a balance sheet of such
Person under GAAP and, for the purposes of this Agreement, the amount of such
obligations at any time shall be the capitalized amount thereof at such time
determined in accordance with GAAP consistently applied.

          "Certificate of Designation" means the Certificate of Designation with
           --------------------------
respect to the Preferred Stock adopted by the Board of Directors and filed with
the Secretary of State of the State of Connecticut on or before the date hereof.

          "Certificate of Incorporation" means the Certificate of Incorporation
           ----------------------------
of the Company in effect on the date hereof.

          "Claims" has the meaning set forth in Section 7.1 of this Agreement.
           ------

          "Closing" has the meaning set forth in Section 2.3 of this Agreement.
           -------

          "Closing Date" has the meaning set forth in Section 2.3 of this
           ------------
Agreement.
<PAGE>

                                                                               3

          "Code" means the internal Revenue Code of 1986, as amended, or any
           ----
successor statute thereto.

          "Commission" means the Securities and Exchange Commission or any
           ----------
similar agency then having jurisdiction to enforce the Securities Act.

          "Common Stock" has the meaning set forth in the recitals to this
           ------------
Agreement.

          "Common Stock Equivalent" means any security or obligation which is by
           -----------------------
its terms convertible into or exchangeable for shares of Common Stock,
including, without limitation, any option, warrant or other subscription or
purchase right with respect to Common Stock.

          "Company" has the meaning set forth in the recitals to this Agreement.
           -------

          "Condition of the Company" means the assets, business, properties,
           ------------------------
prospects, operations or financial condition of the Company.

          "Contractual Obligations" means as to any Person, any provision of any
           -----------------------
security issued by such Person or of any agreement, undertaking, contract,
indenture mortgage, deed of trust or other instrument to which such Person is a
party or by which it or any of its property is bound.

          "Financial Statements" has the meaning set forth in Section 3.6 of
           --------------------
this Agreement.

          "GAAP" means generally accepted accounting principles in effect from
           ----
time to time in the United States.

          "GAP 46" means General Atlantic Partners 46, L.P., a Delaware limited
           ------
partnership.

          "GAP Coinvestment" has the meaning set forth in the recitals to this
           ----------------
Agreement.

          "GAP LLC" means General Atlantic Partners, LLC, a Delaware limited
           -------
liability company and the general partner of GAP LP, and any successor to such
entity.

          "GAP LP" has the meaning set forth in the recitals to this Agreement.
           ------

          "Governmental Authority" means the government of any nation, state,
           ----------------------
city, locality or other political subdivision thereof, any entity exercising
executive, legislative, judicial, regulatory or administrative functions of or
pertaining to government, and any corporation or other entity owned or
controlled, through stock or capital ownership or otherwise, by any of the
foregoing.
<PAGE>

                                                                               4

          "Indemnified Party" has the respective meanings set forth in Sections
           -----------------
7.1 and 7.3 of this Agreement.

          "Indemnifying Party" has the respective meanings set forth in Sections
           ------------------
7.1 and 7.3 of this Agreement.

          "Initial Public Offering" means an underwritten public offering
           -----------------------
pursuant to an effective Registration Statement filed under the Securities Act.

          "IPO Effectiveness Date" means the date upon which the Company
           ----------------------
commences its Initial Public Offering.

          "Lien" means any mortgage, deed of trust, pledge, hypothecation,
           ----
assignment, encumbrance, lien (statutory or other) or preference, priority,
right or other security interest or preferential arrangement of any kind or
nature whatsoever (excluding preferred stock and equity related preferences),
including, without limitation, those created by, arising under or evidenced by
any conditional sale or other title retention agreement, the interest of a
lessor under a Capital Lease Obligation, or any financing lease having
substantially the same economic effect as any of the foregoing.

          "Losses" has the meaning set forth in Section 7.1 of this Agreement.
           ------

          "Minor Stockholders Agreement" has the meaning set forth in Section
           ----------------------------
5.5 of this Agreement.

          "Nonvoting Stock" has the meaning set forth in the recitals to this
           ----------------

Agreement.

          "Orders" has the meaning set forth in Section 3.2 of this Agreement.
           ------

          "Person" means any individual, firm, corporation, partnership, trust,
           ------
incorporated or unincorporated association, joint venture, joint stock company,
limited liability company, Governmental Authority or other entity of any kind,
and shall include any successor (by merger or otherwise) of such entity.

          "Preferred Stock" has the meaning set forth in the recitals to this
           ---------------
Agreement.
<PAGE>

                                                                               5

          "Purchased Shares" has the meaning set forth in Section 2.1 of this
           ----------------
Agreement.

          "Purchaser Indemnified Party" has the meaning set forth in Section 7.2
           ---------------------------
of this Agreement.

          "Purchaser Indemnifying Party" has the meaning set forth in Section
           ----------------------------
7.2 of this Agreement.

          "Purchasers" has the meaning set forth in the recitals to this
           ----------
Agreement.

          "Registration Rights Agreement Amendment" means Amendment No. 1 to the
           ---------------------------------------
Registration Rights Agreement, dated as of March 9, 1998, by and among the
Company, GAP 46, GAP Coinvestment, GAP LP and the Stockholders named therein,
substantially in the form attached hereto as Exhibit B.

          "Registration Statement" means a Registration Statement filed pursuant
           ----------------------
to the Securities Act.

          "Requirement of Law" means, as to any Person, any law, statute,
           ------------------
treaty, rule, regulation, right, privilege, qualification, license or franchise
or determination of an arbitrator or a court or other Governmental Authority or
stock exchange, in each case applicable or binding upon such Person or any of
its property or to which such Person or any of its property is subject or
pertaining to any or all of the transactions contemplated or referred to herein.

          "Sale" shall mean the voluntary sale, conveyance, exchange or transfer
           ----
to another Person of (i) the Voting Stock of the Company if, after such sale,
conveyance, exchange or transfer, the stockholders of the Company prior to such
sale, conveyance, exchange or transfer do not retain at least a majority of the
voting power of the Company or (ii) all or substantially all of the assets of
the Company.

          "Securities Act" means the Securities Act of 1933, as amended, and the
           --------------
rules and regulations of the Commission thereunder.

          "Stockholders Agreement Amendment" means Amendment No. 1 to the
           --------------------------------
Stockholders Agreement, dated as of March 9, 1998 by and among the Company, GAP
46, GAP Coinvestment, GAP LP and the stockholders named therein substantially in
the form attached hereto as Exhibit A.
                            ---------

          "Subsidiaries" means, as of the relevant date of determination, with
           ------------
respect to any Person, a corporation or other Person of which 50% or more of the
voting power of the outstanding voting equity securities or 50% or more of the
outstanding economic equity interest is held, directly or indirectly, by such
Person. Unless otherwise qualified, or the context otherwise requires, all
references to a "Subsidiary" or to "Subsidiaries" in this Agreement shall refer
to a Subsidiary or Subsidiaries of the Company.
<PAGE>

                                                                               6

          "Transaction Documents" means collectively, this Agreement, the
           ---------------------
Stockholders Agreement Amendment and the Registration Rights Agreement
Amendment.

          "Unaudited Financial Statements" has the meaning set forth in Section
           ------------------------------
3.6 of this Agreement.

          "Voting Stock" has the meaning set forth in the recitals to this
           ------------
Agreement.

          1.2  Accounting Terms; Financial Statements.  All accounting terms
               --------------------------------------
used herein not expressly defined in this Agreement shall have the respective
meanings given to them in accordance with sound accounting practice. The term
"sound accounting practice" shall mean such accounting practice as, in the
opinion of the independent certified public accountants regularly retained by
the Company, conforms at the time to GAAP applied on a consistent basis except
for changes with which such accountants concur.

                                   ARTICLE 2

                      PURCHASE AND SALE OF PREFERRED STOCK
                      ------------------------------------

          2.1  Purchase and Sale of Preferred Stock.   Subject to the terms and
               ------------------------------------
conditions herein set forth, the Company agrees to issue and sell to each of the
Purchasers, and each of the Purchasers agrees that it will purchase from the
Company, on the Closing Date, the aggregate number of shares of Preferred Stock
set forth opposite such Purchaser's name on Schedule 2.1 hereto, for the
                                            ------------
aggregate purchase price set forth opposite such Purchaser's name on Schedule
                                                                     --------
2.1 hereto (all of the shares of Preferred Stock being purchased hereunder being
---
referred to herein as the "Purchased Shares").

          2.2  Certificate of Designation.    The Purchased Shares shall be
               --------------------------
shares of preferred stock of the Company issued pursuant to the Certificate of
Designation.

          2.3  Closing.   The closing of the sale and purchase of the Purchased
               -------
Shares (the "Closing") shall take place at the offices of Paul, Weiss, Rifkind,
Wharton & Garrison, no later than 2:00 p.m., New York time, on the date hereof,
or at such other time, place and date that the Company and the Purchasers may
agree in writing (the "Closing Date"). On the Closing Date, the Company shall
deliver to each Purchaser a certificate representing the Purchased Shares being
purchased by such Purchaser against delivery by such Purchaser to the Company of
the aggregate purchase price therefor (as set forth opposite such Purchaser's
name on Schedule 2.1 hereto) by wire transfer of immediately available funds.
        ------------

<PAGE>

                                                                               7

                                   ARTICLE 3

                         REPRESENTATIONS AND WARRANTIES
                                 OF THE COMPANY
                                 --------------

          The Company represents and warrants to the Purchasers as follows:

          3.1  Corporate Existence and Power.   The Company (a) is a corporation
               -----------------------------
duly organized, validly existing and in good standing under the laws of the
jurisdiction of its incorporation, (b) has all requisite corporate power and
authority to own and operate its property, to lease the property it operates as
lessee and to conduct the business in which it is currently, or is proposed to
be, engaged; (c) is duly qualified as a foreign corporation, licensed and in
good standing under the laws of each jurisdiction in which its ownership, lease
or operation of property or the conduct of its business require such
qualification, except where such failure would not result in a material adverse
effect on the Condition of the Company; and (d) has the corporate power and
authority to execute, deliver and perform its obligations under this Agreement
and each of the other Transaction Documents to which it is a party.

          3.2  Authorization; No Contravention.   The execution, delivery and
               -------------------------------
performance by the Company of this Agreement and each of the other Transaction
Documents and the transactions contemplated hereby and thereby (a) have been
duly authorized by all necessary corporate action of the Company; (b) do not
contravene the terms of the Certificate of Incorporation or the By-laws; (c) do
not violate, conflict with or result in any breach or contravention of, or the
creation of any Lien under, any material Contractual Obligation of the Company,
or any Requirement of Law applicable to the Company; and (d) do not violate any
judgment, injunction, writ, award, decree or order of any nature (collectively,
"Orders") of any Governmental Authority against, or binding upon, the Company.

          3.3  Governmental Authorization; Third Party Consents.  No approval,
               ------------------------------------------------
consent, compliance, exemption, authorization or other action by, or notice to,
or filing with, any Governmental Authority or any other Person, and no lapse of
a waiting period under a Requirement of Law, is necessary or required in
connection with the execution, delivery or performance (including, without
limitation, the sale, issuance and delivery of the Purchased Shares) by, or
enforcement against, the Company of this Agreement and the other Transaction
Documents or the transactions contemplated hereby and thereby; provided, however
                                                               --------  -------
that the Company makes no representation regarding any filings or approvals
required pursuant to the Hart-Scott-Rodino Antitrust Improvements Act of 1976,
as amended.
<PAGE>

                                                                               8

          3.4  Binding Effect.   Each of the Transaction Documents has been duly
               --------------
executed and delivered by the Company, and constitutes, the legal, valid and
binding obligations of the Company enforceable against the Company in accordance
with their terms, except as enforceability may be limited by applicable
bankruptcy, insolvency, reorganization, fraudulent conveyance or transfer,
moratorium or similar laws affecting the enforcement of creditors' rights
generally and by general principles of equity relating to enforceability
(regardless of whether considered in a proceeding at law or in equity).

          3.5  Capitalization.   On the Closing Date, after giving effect to the
               --------------
transactions contemplated by this Agreement, the authorized capital stock of the
Company shall consist of (i) 7,500 shares of Voting Stock, of which 2,000 shares
are issued and outstanding and (ii) 7,500 shares of Nonvoting Stock, of which
6,792 shares are issued and outstanding and (iii) 760 shares of Preferred Stock,
of which 703.36 shares will be outstanding and issued to the Purchasers.
Schedule 3.5 sets forth, at and on the Closing Date, a true and complete list of
------------
(x) the stockholders of the Company (including any trust or escrow agent
arrangement created in connection with any employee stock option plan) and,
opposite the name of each stockholder, the amount of all outstanding capital
stock and Common Stock Equivalents owned by such stockholder and (y) the holders
of Common Stock Equivalents (other than the stockholders set forth in clause (x)
above) and, opposite the name of each such holder, the amount of all Common
Stock Equivalents owned by such holder. As of the Closing Date, the Company will
have reserved an aggregate of 703.36 shares of Common Stock for issuance upon
conversion of the Purchased Shares. Except as set forth on Schedule 3.5, there
                                                           ------------
are no options, warrants, conversion privileges, subscription or purchase rights
or other rights presently outstanding to purchase or otherwise acquire (i) any
authorized but unissued, unauthorized or treasury shares of the Company's
capital stock, (ii) any Common Stock Equivalents or (iii) other securities of
the Company. As of the Closing Date, the Purchased Shares will be duly
authorized, and when issued and sold to the Purchasers after payment therefor in
accordance herewith, will be validly issued, fully paid and nonassessable and,
assuming the accuracy of the representations and warranties of the Purchasers
set forth in Article 4, will be issued in compliance with the registration and
qualification requirements of all applicable federal and state securities laws
for pursuant to exemptions therefrom). The shares of Common Stock issuable upon
conversion of the Purchased Shares are duly authorized and, when issued in
compliance with the provisions of the Certificate of Incorporation, will be
validly issued, fully paid and nonassessable. The Company has no Subsidiaries.
<PAGE>

                                                                               9

          3.6  Financial Statements. The Company has delivered to the Purchasers
               --------------------
its Audited Financial Statements for the fiscal year ended December 31, 1997
(the "Audited Financial Statements) and the Unaudited Financial Statements
(balance sheet and statement of operations) for the financial period ending June
30, 1998 (the "Unaudited Financial Statements" and, together with the Audited
Financial Statements, the "Financial Statements"). The Financial Statements have
been prepared in accordance with GAAP applied on a consistent basis throughout
the periods indicated, except that the Unaudited Financial Statements do not
contain footnotes or typical year-end adjustments. The Financial Statements
fully and fairly present the financial position, operating results and cash
flows of the Company as of the respective dates and for the respective periods
indicated, subject, in the case of the Unaudited Financial Statements, to normal
year-end audit adjustments.

          3.7  No Material Adverse Change; Ordinary Course of Business.   Since
               -------------------------------------------------------
March 31, 1998, (a) there has not been any material adverse change, nor to the
knowledge of the Company is any such change threatened, in the Condition of the
Company, (b) the Company has not participated in any transaction or otherwise
acted outside the ordinary course of business, including, without limitation,
declaring or paying any dividend or declaring or making any distribution to its
stockholders except out of the earnings of the Company and (c) the Company has
not increased the compensation of any of its officers or the rate of pay of any
of its employees, except as part of regular compensation increases in the
ordinary course of business.

          3.8  Disclosure.   This Agreement and the documents and certificates
               ----------
furnished to the Purchasers by the Company, taken as a whole, do not contain any
untrue statement of a material fact or to the Company's knowledge omit to state
a material fact necessary in order to make the statements contained herein or
therein, in the light of the circumstances under which they were made, not
misleading.

          3.9  Private Offering.   No form of general solicitation or general
               ----------------
advertising was used by the Company or its representatives in connection with
the sale of the Purchased Shares. Assuming the accuracy of the representations
and warranties of the Purchasers set forth in Article 4, no registration of the
Purchased Shares, pursuant to the provisions of the Securities Act or any state
securities or "blue sky" laws, will be required by the sale of the Purchased
Shares.

          3.10 No Default or Breach; Contractual Obligations.   The Company has
               ---------------------------------------------
not received notice of, and is not in default under or with respect to, any
Contractual Obligation of the Company in any respect, which, individually or
together with all such defaults, could have a material adverse effect on (i) the
Condition of the Company or (ii) the ability of the Company to perform its
obligations under this Agreement or the other Transaction Documents.
<PAGE>

                                                                              10

          3.11 Broker's, Finder's or Similar Fees. There are no brokerage
               ----------------------------------
commissions, finder's fees or similar fees or commissions payable by the Company
in connection with the transactions contemplated hereby based on any agreement,
arrangement or understanding with the Company or any action taken by the
Company.

                                   ARTICLE 4

                        REPRESENTATIONS AND WARRANTIES
                               OF THE PURCHASERS
                               -----------------

          Each of the Purchasers hereby represents and warrants (severally and
not jointly) to the Company as follows:

          4.1  Existence and Power.   Such Purchaser (a) is a partnership duly
               -------------------
organized, validly existing and in good standing under the laws of the
jurisdiction of its formation, (b) has all requisite power and authority to
conduct the business in which it is currently, or is proposed to be, engaged,
and (c) has the requisite partnership power and authority to execute, deliver
and perform its obligations under this Agreement and each of the other
Transaction Documents.

          4.2  Authorization; No Contravention.   The execution, delivery and
               -------------------------------
performance by such Purchaser of this Agreement and each of the other
Transaction Documents and the transactions contemplated hereby and thereby, (a)
have been duly authorized by all necessary partnership action, (b) do not
contravene the terms of such Purchaser's organizational documents, or any
amendment thereof, (c) do not violate, conflict with or result in any breach or
contravention of or the creation of any Lien under, any Contractual Obligation
of such Purchaser, or any Requirement of Law applicable to such Purchaser and
(d) do not violate any Orders of any Governmental Authority against, or binding
upon, such Purchaser.

          4.3  Governmental Authorization; Third Party Consents.   No Approval,
               ------------------------------------------------
consent, compliance, exemption, authorization, or other action by, or notice to,
or filing with, any Governmental Authority or any other Person, and no lapse of
a waiting period under any Requirement of Law is necessary or required in
connection with the execution, delivery or performance (including, without
limitation, the purchase of the Purchased Shares) by, or enforcement against,
such Purchaser of this Agreement and each of the other Transaction Documents or
the transactions contemplated hereby and thereby.

          4.4  Binding Effect.   This Agreement and each of the other
               --------------
Transaction Documents have been duly executed and delivered by each Purchaser,
and constitutes the legal, valid and binding obligations of such Purchaser,
enforceable against it in accordance with their terms, except as enforceability
may be limited by applicable bankruptcy, insolvency, reorganization, fraudulent
conveyance or transfer, moratorium or similar laws affecting the enforcement of
creditors' rights generally or by equitable principles relating to
enforceability (regardless of whether considered in a proceeding at law or in
equity).
<PAGE>

                                                                              11

          4.5  Purchase for Own Account. The Purchased Shares to be acquired by
               ------------------------
such Purchaser pursuant to this Agreement are being or will be acquired for
investment for its own account and with no intention of distributing or
reselling, or granting any participation in, such Purchased Shares or any part
thereof in any transaction that would be in violation of the securities laws of
the United States of America, or any state, without prejudice, however, to the
rights of such Purchaser at all times to sell or otherwise dispose of all or any
part of such Purchased Shares under an effective registration statement under
the Securities Act, or under an exemption from such registration available under
such laws, and subject, nevertheless, to the disposition of such Purchaser's
property being at all times within its control. If such Purchaser should in the
future decide to dispose of any of such Purchased Shares, such Purchaser
understands and agrees that it may do so only in compliance with the Securities
Act and applicable state securities laws, as then in effect. Such Purchaser
agrees to the imprinting, so long as required by law, of legends on certificates
representing all of its Purchased Shares as required by any applicable state
securities laws and to the following effect (and acknowledges that the Company
will make a notation on its transfer books to such effect):

          THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN
          REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE
          "ACT"), OR THE SECURITIES LAWS OF ANY JURISDICTION OF THE
          UNITED STATES. THE SECURITIES MAY NOT BE TRANSFERRED EXCEPT
          PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER SUCH
          ACT AND UNDER THE APPLICABLE STATE SECURITIES LAWS OR
          PURSUANT TO AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO
          THE COMPANY, IF REQUESTED BY THE COMPANY, THAT THERE IS AN
          APPLICABLE EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF
          SUCH ACT AND SUCH LAWS.

          THE SALE, ASSIGNMENT, HYPOTHECATION, PLEDGE ENCUMBRANCE OR
          OTHER DISPOSITION (EACH A "TRANSFER")AND VOTING OF ANY OF
          THE SECURITIES REPRESENTED BY THIS CERTIFICATE ARE
          RESTRICTED BY THE TERMS OF THE AMENDED AND RESTATED
          STOCKHOLDERS AGREEMENT, DATED MARCH 9, 1998, AMONG NEWSUB
          SERVICES, INC. AND THE STOCKHOLDERS NAMED THEREIN. THE
          COMPANY WILL NOT REGISTER THE TRANSFER OF SUCH SECURITIES ON
          THE BOOKS OF THE COMPANY UNLESS AND UNTIL THE TRANSFER HAS
          BEEN MADE IN COMPLIANCE WITH THE TERMS OF THE STOCKHOLDERS
          AGREEMENT. THE COMPANY WILL MAIL A COPY OF SUCH AGREEMENT,
          TOGETHER WITH A COPY OF THE EXPRESS TERMS OF THE SECURITIES
          AND THE OTHER CLASS OR CLASSES AND SERIES OF SHARES, IF ANY,
          WHICH THE COMPANY IS AUTHORIZED TO ISSUE, TO THE RECORD
          HOLDER OF
<PAGE>

                                                                              12

          THIS CERTIFICATE, WITHOUT CHARGE, WITHIN FIVE DAYS AFTER
          RECEIPT OF A WRITTEN REQUEST THEREFOR.

          4.6  Investment Experience. Each oft en the Purchasers is an
               ---------------------
"Accredited Investor" as defined in Rule 501(a) under the Securities Act.

          4.7  Broker's. Finder's or Similar Fees.   There are no brokerage
               ----------------------------------
commissions, finder's fees or similar fees or commissions payable by such
Purchaser, in connection with the transactions contemplated hereby based on any
agreement, arrangement or understanding with such Purchaser or any action taken
by such Purchaser.

                                   ARTICLE 5

                         CONDITIONS TO THE OBLIGATION
                          OF THE PURCHASERS TO CLOSE
                          --------------------------

          The obligation of the Purchasers to purchase the Purchased Shares, to
pay the purchase price therefor at the Closing on the date hereof and to perform
their other obligations hereunder shall be subject to the satisfaction as
determined by, or waiver by, the Purchasers of the following conditions on the
date hereof.

          5.1  Secretary's Certificate.  The Purchasers shall have received a
               -----------------------
certificate from the Company, in form and substance reasonably satisfactory to
the Purchasers, dated the Closing Date and signed by the Secretary or an
Assistant Secretary of the Company, certifying that the attached copies of the
Certificate of Incorporation, the By-laws and resolutions of the Board of
Directors approving this Agreement and each of the other Transaction Documents
and the transactions contemplated hereby and thereby, are all true, complete and
correct and remain unamended and in full force and effect.

          5.2  Stockholders Agreement Amendment.   The Company and the
               --------------------------------
stockholders named therein shall have duly executed and delivered the
Stockholders Agreement Amendment.
<PAGE>

                                                                              13

          5.3  Registration Rights Agreement Amendment. The Company and the
               ---------------------------------------
stockholders named therein shall have duly executed and delivered the
Registration Rights Agreement Amendment.

          5.4  Purchased Shares.   The Company shall have delivered to each of
               ----------------
the Purchasers certificates in definitive form representing the number of
Purchased Shares set forth opposite the name of such Purchaser on Schedule 2.1
                                                                  ------------
hereto.

          5.5  Consents and Approvals.   All consents, exemptions,
               ----------------------
authorizations, or other actions by, or notices to, or filings with,
Governmental Authorities and other Persons in respect of all Requirements of Law
and with respect to all Contractual Obligations (including, without limitation,
under (i) the Shareholder Agreement, dated December 1, 1993 (the "Minor
Stockholders Agreement"), among the Company, Walker, Loeb and the other parties
listed on the signature page thereto, (ii) the Stockholders Agreement dated as
of March 9, 1998, among the Company, GAP 46, GAP Coinvestment and the other
stockholders named therein, and (iii) the Credit Agreement (the "Credit
Agreement"), dated March 5, 1998, by and among the Company, Nationsbank, N.A.,
General Electric Capital Corporation and the lenders party thereto from time to
time) which are necessary or required in connection with the execution, delivery
or performance by, or enforcement against, the Company of this Agreement and
each of the other Transaction Documents shall have been obtained and be in full
force and effect, and the Purchasers shall have been furnished with appropriate
evidence thereof and all applicable waiting periods shall have expired without
any action being taken or threatened which would have a material adverse effect
on the Condition of the Company.

          5.6  Amendment to Certificate of Incorporation.   The Company shall
               -----------------------------------------
have amended, in form and substance reasonably satisfactory to the Purchasers,
its Certificate of Incorporation to provide that each share of Nonvoting Stock
purchased by GAP 46 and GAP Coinvestment, pursuant to the Stock Purchase
Agreement, dated March 9, 1998, shall be automatically converted into and
exchanged for one share of Voting Stock upon the earlier of (i) the IPO
Effectiveness Date and (ii) December 31, 1999.

          5.7  Revised Budget.   The Purchasers shall have received a Revised
               --------------
1998 Budget from the Company, in form and substance reasonably satisfactory to
them.

          5.8  Credit Agreement Amendment.  Any amendment to the Credit
               ---------------------------
Agreement entered into by the Company shall be in form and substance reasonably
satisfactory to the Purchasers.
<PAGE>

                                                                              14

                                   ARTICLE 6

                        CONDITIONS TO THE OBLIGATION OF
                             THE COMPANY TO CLOSE
                             --------------------

          The obligation of the Company to sell the Purchased Shares and to
perform their obligations hereunder shall be subject to the satisfaction as
determined by, or waiver by, the Company of the following conditions on or
before the date hereof:

          6.1  Payment by the Purchasers.   Each Purchaser shall have purchased
               -------------------------
and paid for the Purchased Shares to be purchased by such Purchaser.

                                   ARTICLE 7

                                INDEMNIFICATION
                                ---------------

          7.1  Indemnification by the Company.   Except as otherwise provided in
               ------------------------------
this Article 7, the Company (the "Indemnifying Party") agrees to indemnify,
defend and hold harmless each of the Purchasers and their Affiliates and their
respective officers, directors, agents, employees, subsidiaries, partners,
members and controlling persons (each, an "Indemnified Party") to the fullest
extent permitted by law from and against any and all losses and any and all
actions, proceedings, claims, complaints, disputes, arbitrations or
investigations or written threats thereof (collectively, "Claims") (including
any Claim by a third party), damages, expenses (including reasonable fees,
disbursements and other charges of counsel incurred by the Indemnified Party in
any action between the Indemnifying Party and the Indemnified Party or between
the Indemnified Party and any third party or otherwise) or other liabilities
(collectively, "Losses") resulting from, arising out of or relating to the
breach by the Indemnifying Party of any representation or warranty or covenant
set forth in Article 3, or relating to the breach of any other agreement by the
Indemnifying Party in this Agreement or the other Transaction Documents;
provided, that the Indemnifying Party shall not be liable under this Section 7.1
--------
to an Indemnified Party to the extent that it is finally judicially determined
that such Losses resulted primarily from the material breach by such Indemnified
Party of any warranty, covenant or other agreement of such Indemnified Party
contained in this Agreement or other Transaction Documents; and provided,
                                                                --------
further, that if and to the extent that such indemnification is unenforceable
-------
for any reason, the Indemnifying Party shall make the maximum contribution to
the payment and satisfaction of such Losses which shall be permissible under
applicable laws. Notwithstanding anything to the contrary contained herein, the
amount of any payment by any Indemnifying Party to any Indemnified Party
herewith in respect of any Loss shall not exceed the aggregate purchase price
paid by the Purchasers for the Purchased Shares purchased by the Purchasers
hereunder. In connection with the obligation of the Indemnifying Party to
indemnify for expenses as set forth above, the Indemnifying Party shall, upon
presentation of appropriate invoices containing reasonable detail, reimburse
each Indemnified Party for all such expenses (including reasonable fees,
disbursements and other charges of counsel incurred by the Indemnified Party)
only (i) after the final resolution or disposition of such Claim and (ii) if
such Indemnified Party prevails in such Claim; provided, however, that if an
                                               --------  -------
Indemnified Party is
<PAGE>

                                                                              15

reimbursed hereunder for any expenses, such reimbursement of expenses shall be
refunded to the extent it is finally judicially determined that the 1osses in
question resulted in primarily from the willful misconduct or gross negligence
of such Indemnified Party.

          7.2  Indemnification by Purchasers.   Except as otherwise provided in
               -----------------------------
this Article 7, each of the Purchasers, severally and not jointly (each, a
"Purchaser Indemnifying Party"), agrees to indemnify, defend and hold harmless
the Company and its officers, directors, shareholders, agents, employees,
subsidiaries, partners, members and controlling persons (each, a "Purchaser
Indemnified Party") to the fullest extent permitted by law from and against any
and all Losses resulting from, arising out of or relating to any breach of the
representation or warranty set forth in Sections 4.5, 4.6 or 4.7 herein;
provided, that the Purchaser Indemnifying Party shall not be liable under this
--------
Section 7.2 to a Purchaser Indemnified Party to the extent that it is finally
judicially determined that such Losses resulted primarily from the material
breach by such Purchaser Indemnified Party of any representation, warranty,
covenant or other agreement of such Purchaser Indemnified Party contained in
this Agreement or the other Transaction Documents; and provided, further, that
                                                       --------  -------
if and to the extent that such indemnification is unenforceable for any reason,
the Purchaser Indemnifying Party shall make the maximum contribution to the
payment and satisfaction of such Losses which shall be permissible under
applicable laws. The aggregate amount of indemnification payments payable to the
Purchaser Indemnified Party shall not exceed the aggregate purchase price paid
by such Purchaser Indemnifying Party for its Purchased Shares hereunder.

          7.3  Notification.   Each Indemnified Party or Purchaser Indemnified
               ------------
Party, as the case may be (for purposes of this Section 7.3, an "Indemnified
Party"), under this Article 7 shall, promptly after the receipt of notice of the
commencement of any action, investigation, claim or other proceeding against
such Indemnified Party in respect of which indemnity may be sought from the
Indemnifying Party or Purchaser Indemnifying Party, as the case may be (for
purposes of this Section 7.3, an "Indemnifying Party"), under this Article 7,
notify the Indemnifying Party in writing of the commencement thereof. The
omission of any Indemnified Party to so notify the Indemnifying Party of any
such action shall not relieve the Indemnifying Party from any liability which it
may have to such Indemnified Party (a) other than pursuant to this Article 7 or
(b) under this Article 7 unless, and only to the extent that, such omission
results in the Indemnifying Party's forfeiture of substantive rights or
defenses. In case any such action, claim or other proceeding shall be brought
against any Indemnified Party, and it shall notify the Indemnifying Party of the
commencement thereof, the Indemnifying Party shall be entitled to assume the
defense thereof at its own expense, with counsel satisfactory to such
Indemnified Party in its reasonable judgment; provided, however, that any
                                              --------  -------
Indemnified Party may, at its own expense, retain separate counsel to
participate in such defense at its own expense. Notwithstanding the foregoing,
in any action, claim or proceeding in which both the Indemnifying Party, on the
one hand, and an Indemnified Party, on the other hand, are, or are reasonably
likely to become, a party, such Indemnified Party shall have the right to employ
separate counsel at the expense of the Indemnifying Party and to control its own
defense of such action, claim or proceeding if, in the reasonable opinion of
counsel to such Indemnified Party, a conflict or potential conflict exists
between the Indemnifying Party, on the one hand, and such Indemnified Party, on
the other hand, that would make such separate representation advisable;
provided, however, that the Indemnifying Party shall not be liable for the fees
--------  -------
and expenses of more than one counsel to all Indemnified Parties.  The
Indemnifying Party agrees that it will not,
<PAGE>

                                                                              16

without the prior written consent of the Indemnified Party, settle, compromise
or consent to the entry of any judgment in any pending or threatened claim,
action or proceeding relating to the matters contemplated hereby (if any
Indemnified Party is a party thereto or has been actually threatened to be made
a party thereto) unless such settlement, compromise or consent includes an
unconditional release of each Indemnified Party from all liability arising or
that may arise out of such claim, action or proceeding. The Indemnifying Party
shall not be liable for any settlement of any claim, action or proceeding
effected against an Indemnified Party without the Indemnifying Party's written
consent, which consent shall not be unreasonably withheld. The rights accorded
to an Indemnified Party hereunder shall be in addition to any rights that any
Indemnified Party may have at common law, by separate agreement or otherwise;
provided, however, that notwithstanding the foregoing or anything to the
--------  -------
contrary contained in this Agreement, nothing in this Article 7 should restrict
or limit any rights that any Indemnified Party may have to seek equitable
relief.

                                   ARTICLE 8

                                 MISCELLANEOUS
                                 -------------

          8.1  Survival of Representations and Warranties.   Except for the
               ------------------------------------------
representations and warranties set forth in Sections 3.1, 3.2, 3.4, 3.5, 4.1,
4.2, 4.4, 4.5, 4.6 and 4.7 herein, which shall survive the execution and
delivery of this Agreement, any investigation by or on behalf of the Company or
the Purchasers, or acceptance of the Purchased Shares or termination of this
Agreement, all of the representations and warranties made herein shall survive
the execution and delivery of this Agreement, any investigation by or on behalf
of the Company or the Purchasers, or acceptance of the Purchased Shares or
termination of this Agreement until forty-five (45) days after receipt by the
Purchasers of the Audited Financial Statements of the Company for the fiscal
year ending December 31, 1999.
<PAGE>

                                                                              17

          8.2  Notices. All notices, demands and other communications provided
               -------
for or permitted hereunder shall be made in writing and shall be by registered
or certified first-class mail, return receipt requested, telecopier, courier
service or personal delivery to the addresses set forth on Schedule 8.2. All
                                                           ------------
such notices and communications shall be deemed to have been duly given when
delivered by hand, if personally delivered; when delivered by courier, if
delivered by commercial courier service; five (5) Business Days after being
deposited in the mail, postage prepaid, if mailed; and when receipt is
mechanically acknowledged, if properly telecopied.

          8.3  Successors and Assigns; Third Party Beneficiaries.  This
               -------------------------------------------------
Agreement shall inure to the benefit of and be binding upon the successors and
permitted assigns of the parties hereto. Subject to applicable securities laws,
each of the Purchasers may assign any of its rights under this Agreement to any
of its Affiliates upon notice to the Company, provided such Affiliate is not
directly or indirectly engaged in a business competitive with the business of
the Company. The Company may not assign any of its rights under this Agreement
without the written consent of the Purchasers. Except as provided in Article 7,
no Person other than the parties hereto and their successors and permitted
assigns is intended to be a beneficiary of this Agreement.

          8.4  Amendment and Waiver.
               --------------------

               (a)  No failure or delay on the part of the Company or the
      Purchasers in exercising any right, power or remedy hereunder shall
      operate as a waiver thereof, nor shall any single or partial exercise of
      any such right, power or remedy preclude any other or further exercise
      thereof or the exercise of any other right, power or remedy. The remedies
      provided for herein are cumulative and are not exclusive of any remedies
      that may be available to the Company or the Purchasers at law, in equity
      or otherwise.

               (b)  Any amendment, supplement or modification of or to any
      provision of this Agreement, any waiver of any provision of this
      Agreement, and any consent to any departure by the Company or the
      Purchasers from the terms of any provision of this Agreement, shall be
      effective only if it is made or given in writing and signed by the Company
      and the Purchasers.

          8.5  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.
<PAGE>

                                                                              18

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

          8.7  Pronouns.   All pronouns and any variations thereof refer to the
               --------
masculine, feminine or neuter, singular or plural, as the context may require.

          8.8  GOVERNING LAW.   THIS AGREEMENT SHALL BE GOVERNED BY AND
               -------------
CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK, WITHOUT REGARD
TO THE PRINCIPLES OF CONFLICTS OF LAW OF ANY JURISDICTION.

          8.9  Severability.   If any one or more of the provisions contained
               ------------
herein, or the application thereof in any circumstance, is held invalid, illegal
or unenforceable in any respect for any reason, the validity, legality and
enforceability of any such provision in every other respect and of the remaining
provisions hereof shall not be in any way impaired, unless the provisions held
invalid, illegal or unenforceable shall substantially impair the benefits of the
remaining provisions hereof.

          8.10 Entire Agreement.   This Agreement, together with the exhibits
               ----------------
and schedules hereto and the other Transaction Documents, is intended by the
parties as a final expression of their agreement and intended to be a complete
and exclusive statement of the agreement and understanding of the parties hereto
in respect of the subject matter contained herein and therein. There are no
restrictions, promises, warranties or undertakings, other than those set forth
or referred to herein or therein. This Agreement, together with the exhibits
hereto, and the other Transaction Documents supersede all prior agreements and
understandings between the parties with respect to such subject matter.

          8.11 Fees.   Upon the Closing, the Company shall reimburse the
               ----
Purchasers for their fees, disbursements and other charges of counsel incurred
in connection with the transactions contemplated by this Agreement, provided
that the amount of such reimbursement shall not exceed $20,000.

          8.12 Publicity.   Except as may be required by any applicable
               ---------
Requirement of law, none of the parties hereto shall issue a publicity release
or public announcement or otherwise make any public disclosure concerning this
Agreement or the transactions contemplated hereby, without prior approval by the
other parties hereto (which approval shall not be unreasonably withheld);
provided, however, that nothing in this Agreement shall restrict any Purchaser
--------  -------
from disclosing information (a) that is already publicly available; (b) to the
prospective transferee in connection with any contemplated transfer of any of
the Purchased Shares; and (c) to its attorneys, accountants, consultants and
other advisors to the extent necessary to obtain their services in connection
with such Purchaser's investment in the Company. In addition, GAP LLC shall be
permitted to disclose its ownership of the Purchased Shares, the aggregate
purchase price therefor and the identity of the Company and its Chief Executive
Officer on its worldwide web page, www.gapartners.com.  If any announcement is
                                   ------------------
required by any applicable Requirement of Law to be made by any party hereto,
prior to making such announcement such party will deliver a draft of such
announcement to the other parties and shall give the other parties an
opportunity to comment thereon.
<PAGE>

                                                                              19

          8.13 Further Assurances.   Each of the parties shall execute such
               ------------------
documents and perform such further acts (including, without limitation,
obtaining any consents, exemptions, authorizations or other actions by, or
giving any notices to, or making any filings with, any Governmental Authority or
any other Person, and otherwise fulfilling, or causing the fulfillment of, the
conditions to Closing set forth in Articles 5 and 6) as may be reasonably
required or desirable to carry out or to perform the provisions of this
Agreement and to consummate and make effective as promptly as possible the
transactions contemplated by this Agreement.

                 [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]
<PAGE>

          IN WITNESS WHEREOF, the parties hereto have caused this Agreement to
be executed and delivered by their respective officers hereunto duly authorized
on the date first above written.

                              NEWSUB SERVICES, INC.


                              /s/: Michael R. Loeb
                                   -------------------------------------
                                      Name:  Michael R. Loeb
                                      Title: President

                              GENERAL ATLANTIC PARTNERS 49, L.P.

                              BY:  GENERAL ATLANTIC PARTNERS, LLC,
                                   Its General Partner

                              /s/: Franchon M. Smithson
                                   -------------------------------------
                                      Name:  Franchon M. Smithson
                                      Title: A Managing Member

                              GAP COINVESTMENT PARTNERS, L.P.


                              /s/:  Franchon M. Smithson
                                   -------------------------------------
                                      Name:  Franchon M. Smithson
                                      Title: A General Partner
<PAGE>

                                 SCHEDULE 2.1


                     Purchase and Sale of Preferred Stock
                     ------------------------------------



Purchaser               Purchased Shares           Purchase Price
---------               ----------------           --------------

GAP LP                       568.15                $16,155,313.00

GAP Coinvestment             135.21                $ 3,844,687.00

     Total:                  703.36                $20,000,000.00