<PAGE>   1
                                                                   Exhibit 10.47


                            STOCK EXCHANGE AGREEMENT


                                 by and between


                                   YAHOO! INC.


                                       and


                                 NET2PHONE, INC.


                           Dated as of March 30, 2000
<PAGE>   2
                            STOCK EXCHANGE AGREEMENT

         THIS STOCK EXCHANGE AGREEMENT is made and entered into as of March 30,
2000, by and between Yahoo! Inc., a Delaware corporation (the "YAHOO!"), and
Net2Phone, Inc., a Delaware corporation ("NET2PHONE").

         THE PARTIES AGREE AS FOLLOWS:

                                    ARTICLE I
                         AUTHORIZATION AND SALE OF STOCK

         Section 1.1 Authorization of the Shares. Yahoo! has authorized the
issuance and exchange of 806,452 shares of Common Stock of Yahoo!, par value
$0.001 per share (the "YAHOO! SHARES"), at a price per share equal to [****],
and Net2Phone has authorized the issuance and exchange of 2,777,778 shares of
Common Stock of Net2Phone, par value $0.01 per share (the "NET2PHONE SHARES"),
at a price per share equal to [****], all pursuant to the terms and conditions
of this Agreement.

         Section 1.2 Exchange of Shares. Subject to the terms and conditions
hereof, contemporaneously with the execution of this Agreement, Yahoo! will
issue to Net2Phone the Yahoo! Shares in exchange for the Net2Phone Shares, and
Net2Phone shall issue to Yahoo! the Net2Phone Shares in exchange for the Yahoo!
Shares.

                                   ARTICLE II
                             CLOSING DATE; DELIVERY

         Section 2.1 Closing Date. The consummation of the exchange of the
Yahoo! Shares and the Net2Phone Shares hereunder (the "CLOSING") shall be held
at the offices of Venture Law Group, A Professional Corporation, 2800 Sand Hill
Road, Menlo Park, California, contemporaneously with the execution of this
Agreement or at such other time and place as Yahoo! and Net2Phone mutually agree
upon in writing (the "CLOSING DATE").

         Section 2.2 Delivery. At the Closing, Yahoo! shall deliver to Net2Phone
certificate(s) representing the Yahoo! Shares and Net2Phone shall deliver to
Yahoo! certificate(s) representing the Net2Phone Shares.

                                   ARTICLE III
                    REPRESENTATIONS AND WARRANTIES OF YAHOO!

         Yahoo! hereby represents and warrants to Net2Phone, at and as of the
date of this Agreement and at and as of the Closing Date, as follows:

         Section 3.1 Organization Yahoo! is a corporation duly organized,
validly existing and in good standing under the laws of the State of Delaware
and has all requisite corporate power to own, lease and operate its property and
to carry on its business as now being conducted and is duly qualified or
licensed to do business and is in good standing in each jurisdiction in which
the
<PAGE>   3
failure to be so qualified or licensed would be reasonably likely to have a
material adverse effect on the business, assets (including intangible assets),
liabilities, condition (financial or otherwise), prospects, value, property or
results or operations (a "MATERIAL ADVERSE EFFECT") of Yahoo!.

         Section 3.2 Valid Issuance of Common Stock. The Yahoo! Shares, when
issued and paid for in accordance with this Agreement will be duly authorized,
validly issued, fully paid, and non-assessable, and issued in compliance with
all applicable federal or state securities laws.

         Section 3.3 Authority; No Conflict; Required Filings and Consents.

                  (a) Yahoo! has all requisite corporate power and authority to
enter into this Agreement and to consummate the transactions contemplated by
this Agreement, including the acquisition of the Net2Phone Shares. The execution
and delivery of this Agreement and the consummation of the transactions
contemplated by this Agreement have been duly authorized by all necessary
corporate action on the part of Yahoo!. This Agreement has been duly executed
and delivered by Yahoo!, and constitutes the valid and binding obligation of
Yahoo!, enforceable in accordance with its terms, except to the extent that
enforceability may be limited by applicable bankruptcy, reorganization,
insolvency, moratorium or other laws affecting the enforcement of creditors'
rights generally and by general principles of equity.

                  (b) The execution and delivery by Yahoo! of this Agreement
does not, and consummation of the transactions contemplated by this Agreement
will not, (i) conflict with, or result in any violation or breach of any
provision of the Certificate of Incorporation or Bylaws of Yahoo!, (ii) result
in any violation or breach of, or constitute (with or without notice or lapse of
time, or both) a default (or give rise to a right of termination, cancellation
or acceleration of any obligation or loss of any material benefit) under any of
the terms, conditions or provisions of any note, bond, mortgage, indenture,
lease, contract or other agreement, instrument or obligation to which Yahoo! is
a party or by which any of its properties or assets may be bound, or (iii)
conflict or violate any permit, concession, franchise, license, judgment, order,
decree, statute, law, ordinance, rule or regulation applicable to Yahoo! or any
of its properties or assets, except in the case of (ii) and (iii) for any such
conflicts, violations, defaults, terminations, cancellations or accelerations
which would not be reasonably likely to have a Material Adverse Effect on Yahoo!
and its subsidiaries, taken as a whole.

                  (c) No consent, approval, order or authorization of, or
registration, declaration or filing with, any court, administrative agency or
commission or other governmental authority or instrumentality ("GOVERNMENTAL
ENTITY") is required by or with respect to Yahoo! in connection with the
execution and delivery of this Agreement or the consummation of the transactions
contemplated hereby, except for (i) such consents, approvals, orders,
authorizations, registrations, declarations and filings as may be required under
applicable federal and state securities laws and the laws of any foreign
country, and (ii) such other consents, authorizations, filings, approvals and
registrations which, if not obtained or made, would be reasonably expected to
have a Material Adverse Effect on Yahoo! and its subsidiaries, taken as a whole.

         Section 3.4 Commission Filings; Financial Statements.

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                  (a) Yahoo! has filed with the Securities and Exchange
Commission (the "COMMISSION") and made available to Net2Phone or its
representatives all forms, reports and documents required to be filed by Yahoo!
with the Commission since [****] (collectively, the "YAHOO! COMMISSION
REPORTS"). Yahoo! Commission Reports (i) at the time filed, complied in all
material respects with the applicable requirements of the Securities Act of
1933, as amended, (the "SECURITIES ACT"), and the Securities Exchange Act of
1934, as amended (the "EXCHANGE ACT"), as the case may be, and (ii) did not at
the time they were filed (or if amended or superseded by a filing prior to the
date of this Agreement, then on the date of such filing) contain any untrue
statement of a material fact or omit to state a material fact required to be
stated therein or necessary in order to make the statements therein, in the
light of the circumstances under which they were made, not misleading.

                  (b) Each of the financial statements (including, in each case,
any related notes) contained in Yahoo! Commission Reports, including any such
Report filed after the date of this Agreement until the Closing, complied as to
form in all material respects with the applicable published rules and
regulations of the Commission with respect thereto, was prepared in accordance
with generally accepted accounting principles applied on a consistent basis
throughout the periods involved (except as may be indicated in the notes to such
financial statements or, in the case of unaudited statements, as permitted by
Form 10-Q of the Commission) and fairly presented the consolidated financial
position of Yahoo! and its subsidiaries as at the respective dates and the
consolidated results of its operations and cash flows for the periods indicated,
except that the unaudited interim financial statements were or are subject to
normal and recurring year-end adjustments which were not or are not expected to
be material in amount.

         Section 3.5 Purchase Entirely for Own Account. The Net2Phone Shares to
be acquired by Yahoo! will be acquired for investment for Yahoo!'s own account,
not as a nominee or agent, and not with a view to the resale or distribution of
any part thereof, and that Yahoo! has no present intention of selling, granting
any participation in, or otherwise distributing the same. Yahoo! further
represents that it does not presently have any contract, undertaking, agreement
or arrangement with any person to sell, transfer or grant participation to such
person or to any third person, with respect to any of the Net2Phone Shares.

         Section 3.6 Investment Experience. Yahoo! is an "accredited investor"
as defined in Rule 501(a) under the Securities Act. Yahoo! is aware of
Net2Phone's business affairs and financial condition and has had access to and
has acquired sufficient information about Net2Phone to reach an informed and
knowledgeable decision to acquire the Net2Phone Shares. Yahoo! has such business
and financial experience as is required to give it the capacity to protect its
own interests in connection with the purchase of the Net2Phone Shares.

         Section 3.7 Restricted Securities. Yahoo! understands that the
Net2Phone Shares are characterized as "restricted securities" under applicable
U.S. federal and state securities laws inasmuch as they are being acquired from
Net2Phone in a transaction not involving a public offering and that, pursuant to
these laws and applicable regulations, Yahoo! must hold the Net2Phone Shares
indefinitely unless they are registered with the Commission and qualified by

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state authorities, or an exemption from such registration and qualification
requirements is available. Yahoo! further acknowledges that if an exemption from
registration or qualification is available, it may be conditioned on various
requirements including, but not limited to, the time and manner of sale, the
holding period for the Net2Phone Shares, and on requirements relating to
Net2Phone which are outside of Yahoo!'s control, and which Net2Phone is under no
obligation and may not be able to satisfy. In this connection, Yahoo! represents
that it is familiar with SEC Rule 144, as presently in effect, and understands
the resale limitations imposed thereby and by the Securities Act.

         Section 3.8 Legends. Yahoo! understands that the Net2Phone Shares, and
any securities issued in respect thereof or exchange therefor, may bear one or
all of the following legends:

                  (a) "THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT
BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AND HAVE BEEN ACQUIRED FOR
INVESTMENT AND NOT WITH A VIEW TO, OR IN CONNECTION WITH, THE SALE OR
DISTRIBUTION THEREOF. THESE SECURITIES MAY NOT BE OFFERED, SOLD, TRANSFERRED OR
OTHERWISE DISPOSED OF UNLESS REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
AMENDED, AND ANY APPLICABLE STATE SECURITIES LAWS OR AN EXEMPTION FROM SUCH
REGISTRATION IS AVAILABLE."

                  (b) Any legend required by the Blue Sky laws of any state to
the extent such laws are applicable to the shares represented by the certificate
so legended.

         Section 3.9 Issuance and Registration of Yahoo! Shares. The Yahoo!
Shares to be issued to Net2Phone pursuant to this Agreement shall be issued
pursuant to the registration statement on Form S-4 filed by Yahoo! with the
Commission on January 12, 2000 (the "SHELF REGISTRATION STATEMENT"), and as such
[****]


                                   ARTICLE IV
                   REPRESENTATIONS AND WARRANTIES OF NET2PHONE

         Net2Phone hereby represents and warrants to Yahoo!, at and as of the
date of this Agreement and at and as of the Closing, as follows:

         Section 4.1 Organization Net2Phone is a corporation duly organized,
validly existing and in good standing under the laws of the State of Delaware
and has all requisite corporate power to own, lease and operate its property and
to carry on its business as now being conducted and is duly qualified or
licensed to do business and is in good standing in each jurisdiction in which
the failure to be so qualified or licensed would be reasonably likely to have a
Material Adverse Effect on Net2Phone.

         Section 4.2 Valid Issuance of Common Stock. The Net2Phone Shares, when
issued and paid for in accordance with this Agreement will be duly authorized,
validly issued, fully

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paid, and non-assessable and issued in compliance with all applicable federal or
state securities laws.

         Section 4.3 Authority; No Conflict; Required Filings and Consents.

                  (a) Net2Phone has all requisite corporate power and authority
to enter into this Agreement and to consummate the transactions contemplated by
this Agreement, including the acquisition of the Yahoo! Shares. The execution
and delivery of this Agreement and the consummation of the transactions
contemplated by this Agreement have been duly authorized by all necessary
corporate action on the part of Net2Phone. This Agreement has been duly executed
and delivered by Net2Phone, and constitutes the valid and binding obligation of
Net2Phone, enforceable in accordance with its terms, except to the extent that
enforceability may be limited by applicable bankruptcy, reorganization,
insolvency, moratorium or other laws affecting the enforcement of creditors'
rights generally and by general principles of equity.

                  (b) The execution and delivery by Net2Phone of this Agreement
does not, and consummation of the transactions contemplated by this Agreement
will not, (i) conflict with, or result in any violation or breach of any
provision of the Certificate of Incorporation or Bylaws of Net2Phone, (ii)
result in any violation or breach of, or constitute (with or without notice or
lapse of time, or both) a default (or give rise to a right of termination,
cancellation or acceleration of any obligation or loss of any material benefit)
under any of the terms, conditions or provisions of any note, bond, mortgage,
indenture, lease, contract or other agreement, instrument or obligation to which
Net2Phone is a party or by which any of its properties or assets may be bound,
or (iii) conflict or violate any permit, concession, franchise, license,
judgment, order, decree, statute, law, ordinance, rule or regulation applicable
to Net2Phone or any of its properties or assets, except in the case of (ii) and
(iii) for any such conflicts, violations, defaults, terminations, cancellations
or accelerations which would not be reasonably likely to have a Material Adverse
Effect on Net2Phone and its subsidiaries, taken as a whole.

                  (c) No consent, approval, order or authorization of, or
registration, declaration or filing with, any Governmental Entity is required by
or with respect to Net2Phone in connection with the execution and delivery of
this Agreement or the consummation of the transactions contemplated hereby,
except for (i) such consents, approvals, orders, authorizations, registrations,
declarations and filings as may be required under applicable federal and state
securities laws and the laws of any foreign country, and (iii) such other
consents, authorizations, filings, approvals and registrations which, if not
obtained or made, would be reasonably expected to have a Material Adverse Effect
on Net2Phone and its subsidiaries, taken as a whole.

         Section 4.4 Commission Filings; Financial Statements.

                  (a) Net2Phone has filed with the Commission and made available
to Net2Phone or its representatives all forms, reports and documents required to
be filed by Net2Phone with the Commission since [****] (collectively, the
"NET2PHONE COMMISSION REPORTS"). Net2Phone Commission Reports (i) at the time
filed, complied in all material respects with the applicable requirements of the
Securities Act, and the Exchange Act, as the case may be, and (ii) did not at
the time they were filed (or if amended or superseded by a filing prior

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to the date of this Agreement, then on the date of such filing) contain any
untrue statement of a material fact or omit to state a material fact required to
be stated therein or necessary in order to make the statements therein, in the
light of the circumstances under which they were made, not misleading.

                  (b) Each of the financial statements (including, in each case,
any related notes) contained in Net2Phone Commission Reports, including any such
Report filed after the date of this Agreement until the Closing, complied as to
form in all material respects with the applicable published rules and
regulations of the Commission with respect thereto, was prepared in accordance
with generally accepted accounting principles applied on a consistent basis
throughout the periods involved (except as may be indicated in the notes to such
financial statements or, in the case of unaudited statements, as permitted by
Form 10-Q of the Commission) and fairly presented the consolidated financial
position of Net2Phone and its subsidiaries as at the respective dates and the
consolidated results of its operations and cash flows for the periods indicated,
except that the unaudited interim financial statements were or are subject to
normal and recurring year-end adjustments which were not or are not expected to
be material in amount.

         Section 4.5 Access to Information. Net2Phone acknowledges that it has
received and reviewed a copy of the Shelf Registration Statement (including the
prospectus therein), together with Amendment No. 1 thereto (including the
prospectus therein) filed by Yahoo! with the Commission on February 11, 2000.

                                    ARTICLE V
                                    COVENANTS

         Section 5.1 Post-Closing Lock-Up for Net2Phone.

                  (a) Net2Phone agrees that:

                           (i) Net2Phone will not sell in the open market [****]
         of the Yahoo! Shares (subject to adjustment for future stock splits,
         dividends and the like) in any [****], without the prior written
         approval of Yahoo!;

                           (ii) during [****] period commencing on the Closing
         Date, Net2Phone will not sell in the open market [****] of the original
         number of Yahoo! Shares issued to Net2Phone pursuant to this Agreement;

                           (iii) during [****] period commencing on the Closing
         Date, Net2Phone will not sell in the open market [****] of the original
         number of Yahoo! Shares issued to Net2Phone pursuant to this Agreement;
         and

                           (iv) following such [****] period, Net2Phone shall be
         free to [****] of the Yahoo! Shares without restriction under this
         Section 5.1 (other than the restriction set forth in Section 5.1(a)(i)
         above).

                                      -vi-
<PAGE>   8
                  (b) Notwithstanding the foregoing, Net2Phone may sell or
otherwise transfer any of the Yahoo! Shares (i) to any wholly-owned subsidiary
of Net2Phone; provided, however, that in any such case, it shall be a condition
to the transfer that the subsidiary execute an agreement stating that it is
receiving and holding such capital stock subject to the provisions of this
Agreement and there shall be no further transfer of such capital stock except in
accordance with this Agreement, and provided further that any such transfer
shall not involve a disposition for value; or (ii) with the prior written
consent of Yahoo!. Net2Phone also agrees and consents to the entry of stop
transfer instructions with Yahoo!'s transfer agent and registrar against the
transfer of the Yahoo! Shares except in compliance with the foregoing
restrictions.

                  (c) Further, notwithstanding anything to the contrary in this
Section 5.1, in the event that the Board of Directors of Net2Phone, following
consultation with its legal counsel, reasonably concludes in good faith that it
is required to transfer all or a portion of the Yahoo! Shares to avoid a
requirement to register under the Investment Company Act of 1940, as amended
(the "Investment Company Act"), Net2Phone shall so notify Yahoo! and may
thereafter sell any shares it deems necessary to avoid any such registration or
other requirements under the Investment Company Act.

         Section 5.1 Post-Closing Lock-Up for Yahoo!.

                  (a) Yahoo! agrees that:

                           (ii) during [****] period commencing on the Closing
         Date, Yahoo! will not sell in the open market [****] of the original
         number of Net2Phone Shares issued to Yahoo! pursuant to this Agreement;

                           (iii) during 180-day period commencing on the Closing
         Date, Yahoo! will not sell in the open market more than two-thirds of
         the original number of Net2Phone Shares issued to Yahoo! pursuant to
         this Agreement; and

                           (iv) following such [****] period, Yahoo! shall be
         free to [****] of the Net2Phone Shares without restriction under this
         Section 5.2.

                  (b) Notwithstanding the foregoing, Yahoo! may sell or
otherwise transfer any of the Net2Phone Shares (i) to any wholly-owned
subsidiary of Yahoo!; provided, however, that in any such case, it shall be a
condition to the transfer that the subsidiary execute an agreement stating that
it is receiving and holding such capital stock subject to the provisions of this
Agreement and there shall be no further transfer of such capital stock except in
accordance with this Agreement, and provided further that any such transfer
shall not involve a disposition for value; or (ii) with the prior written
consent of Net2Phone. Yahoo! also agrees and consents to the entry of stop
transfer instructions with Net2Phone's transfer agent and registrar against the
transfer of the Net2Phone Shares except in compliance with the foregoing
restrictions.

         Section 5.3 Public Disclosure. Yahoo! and Net2Phone shall consult with
each other, and to the extent practicable, agree, before issuing any press
release or otherwise making any public statement with respect to the
transactions contemplated by this Agreement and will not

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issue any such press release or make any such public statement prior to such
consultation, except as may be required by law or any listing agreement with the
Nasdaq Stock Market or a national securities exchange.


                                   ARTICLE VI
                                  MISCELLANEOUS

         Section 6.1 Governing Law. This Agreement shall be governed in all
respects by the laws of the State of Delaware (without reference to its
conflicts of laws principles).

         Section 6.2 Survival. The representations, warranties, covenants and
agreements made herein shall survive the closing of the transactions
contemplated hereby.

         Section 6.3 Successors and Assigns. Except as otherwise expressly
provided herein, the provisions hereof shall inure to the benefit of, and be
binding upon, the successors, assigns, heirs, executors and administrators of
the parties hereto.

         Section 6.4 Entire Agreement; Amendment. This Agreement and the other
documents delivered pursuant hereto constitute the full and entire understanding
and agreement among the parties with regard to the subjects hereof and thereof.
Any term of this Agreement may be amended and the observance of any term of this
Agreement may be waived (either generally or in a particular instance and either
retroactively or prospectively), only with the written consent of Yahoo! and
Net2Phone.

         Section 6.5 Notices and Other Communications. Every notice or other
communication required or contemplated by this Agreement by either party shall
be delivered either by (i) personal delivery, (ii) postage prepaid return
receipt requested registered or certified mail or the equivalent of registered
or certified mail under the laws of the country where mailed, (iii) nationally
recognized overnight courier, such as Federal Express or UPS, or (iv) facsimile
with a confirmation copy sent simultaneously by postage prepaid, return receipt
requested, registered or certified mail, in each case addressed to Yahoo! or
Net2Phone as the case may be at the following address:

         To Yahoo!:          Yahoo! Inc.
                             3420 Central Expressway
                             Santa Clara, CA 95051
                             Attn:  Senior Vice President, Corporate Development
                             Facsimile:  (408) 328-7939

                                     -viii-
<PAGE>   10
                             With a copy at the same address to the
                             attention of the General Counsel, and a copy
                             to:

                             Venture Law Group
                             A Professional Corporation
                             2800 Sand Hill Road
                             Menlo Park, California 94025
                             Attn.:  Steven J. Tonsfeldt
                                     Keith A. Miller
                             Facsimile:  (415) 233-8386

         To Net2Phone:       Net2Phone, Inc.
                             171 Main Street
                             Hackensack, New Jersey 07601
                             Attn:  Chief Executive Officer
                             Facsimile: (

                             With a copy to:

                             Kirkland & Ellis
                             Aon Center
                             200 East Randolph Drive
                             Chicago, Illinois 60601
                             Attn:  Richard W. Porter
                             Facsimile:  (312) 861-2200

or at such other address as the intended recipient previously shall have
designated by written notice to the other party (with copies to counsel as may
be indicated on the signature page). Notice by registered or certified mail
shall be effective on the date it is officially recorded as delivered to the
intended recipient by return receipt or equivalent, and in the absence of such
record of delivery, the effective date shall be presumed to have been the fifth
(5th) business day after it was deposited in the mail. All notices delivered in
person or sent by courier shall be deemed to have been delivered to and received
by the addressee and shall be effective on the date of personal delivery;
notices delivered by facsimile with simultaneous confirmation copy by registered
or certified mail shall be deemed delivered to and received by the addressee and
effective on the date sent. Notice not given in writing shall be effective only
if acknowledged in writing by a duly authorized representative of the party to
whom it was given.

         Section 6.6 Delays or Omissions. No delay or omission to exercise any
right, power or remedy accruing to any holder of any Shares, upon any breach or
default of Yahoo! under this Agreement, shall impair any such right, power or
remedy of such holder nor shall it be construed to be a waiver of any such
breach or default, or an acquiescence therein, or of or in any similar breach or
default thereafter occurring; nor shall any waiver of any single breach or
default be deemed a waiver of any other breach or default theretofore or
thereafter occurring. Any waiver, permit, consent or approval of any kind or
character on the part of any holder of any breach or


                                      -ix-
<PAGE>   11
default under this Agreement, or any waiver on the part of any holder of any
provisions or conditions of this Agreement, must be in writing and shall be
effective only to the extent specifically set forth in such writing. All
remedies either under this Agreement, or by law or otherwise afforded to any
holder, shall be cumulative and not alternative.

         Section 6.7 Severability. In case any provision of this Agreement shall
be invalid, illegal or unenforceable, the validity, legality and enforceability
of the remaining provisions shall not in any way be affected or impaired
thereby.

         Section 6.8 Finder's Fees.

                  (a) Yahoo! (i) represents and warrants that it has retained no
finder or broker in connection with the transactions contemplated by this
Agreement and (ii) hereby agrees to indemnify and to hold Net2Phone harmless of
and from any liability for commission or compensation in the nature of a
finder's fee to any broker or other person or firm (and the costs and expenses
of defending against such liability or asserted liability) for which Yahoo!, or
any of its employees or representatives, is responsible.

                  (b) Net2Phone (i) represents and warrants that it has retained
no finder or broker in connection with the transactions contemplated by this
Agreement and (ii) hereby agrees to indemnify and to hold Yahoo! harmless of and
from any liability for any commission or compensation in the nature of a
finder's fee to any broker or other person or firm (and the costs and expenses
of defending against such liability or asserted liability) for which Net2Phone,
or any of its employees or representatives, is responsible.

         Section 6.9 California Corporate Securities Law. THE SALE OF THE
SECURITIES WHICH ARE THE SUBJECT OF THIS AGREEMENT HAS NOT BEEN QUALIFIED WITH
THE COMMISSIONER OF CORPORATIONS OF THE STATE OF CALIFORNIA, AND THE ISSUANCE OF
SUCH SECURITIES OR THE PAYMENT OR RECEIPT OF ANY PART OF THE CONSIDERATION
THEREFOR PRIOR TO SUCH QUALIFICATION IS UNLAWFUL, UNLESS THE SALE OF SECURITIES
IS EXEMPT FROM THE QUALIFICATION BY SECTION 25100, 25102, OR 25105 OF THE
CALIFORNIA CORPORATIONS CODE. THE RIGHTS OF ALL PARTIES TO THIS AGREEMENT ARE
EXPRESSLY CONDITIONED UPON SUCH QUALIFICATION BEING OBTAINED, UNLESS THE SALE IS
SO EXEMPT.

         Section 6.10 Counterparts. This Agreement may be executed in any number
of counterparts, each of which shall be an original, but all of which together
shall constitute one instrument. Execution and delivery of this Agreement by
exchange of facsimile copies bearing the facsimile signature of a party hereto
shall constitute a valid and binding execution and delivery of this Agreement by
such party. Such facsimile copies shall constitute enforceable original
documents.

         Section 6.11 Attorneys' Fees. If any action or proceeding shall be
commenced to enforce this Agreement or any right arising in connection with this
Agreement, the prevailing party in such action or proceeding shall be entitled
to recover from the other party, the reasonable

                                      -x-
<PAGE>   12
attorneys' fees, costs and expenses incurred by such prevailing party in
connection with such action or proceeding or negotiation to avoid such action or
proceeding.

                                      -xi-
<PAGE>   13
         IN WITNESS WHEREOF, the parties have executed this Agreement as of the
day and year set forth in the first paragraph hereof.

                                    YAHOO! INC.


                                    By: /s/ Jeff Mallett
                                    Name:  Jeff Mallett
                                    Title: President and Chief Operating Officer


                                    NET2PHONE, INC.


                                    By:  /s/ Howard Balter
                                    Name:  Howard Balter
                                    Title: Chief Executive Officer

                                     -xii-