<PAGE>

                                                                     Exhibit 3.1
                                                                     -----------

               AMENDED AND RESTATED CERTIFICATE OF INCORPORATION

                                      OF

                               OPEN MARKET, INC.

                       Pursuant to Sections 242 and 245
                        of the General Corporation Law
                           of the State of Delaware


     OPEN MARKET, INC., (the "Corporation"), a corporation organized and
existing under and by virtue of the General Corporation Law of the State of
Delaware (the "General Corporation Law"), hereby certifies as follows:

     1.  The name of the corporation is Open Market, Inc.  The corporation was
originally incorporated on December 6, 1993.

     2.  This Amended and Restated Certificate of Incorporation restates and
integrates and further amends the Certificate of Incorporation of the
Corporation, was duly adopted in accordance with the provisions of Sections 242
and 245 of the General Corporation Law, and was approved by written consent of
the stockholders of the Corporation given in accordance with the provisions of
Section 228 of the General Corporation Law (prompt notice of such action having
been given to those stockholders who did not consent in writing).  The
resolution setting forth the Amended and Restated Certificate of Incorporation
is as follows:

RESOLVED:  That the Certificate of Incorporation of the Corporation, as amended,
--------
be and hereby is amended and restated in its entirety so that the same shall
read as follows:

     FIRST.  The name of the Corporation is:

                    Open Market, Inc.

     SECOND. The address of its registered office in the State of Delaware is
Corporation Trust Center, 1209 Orange Street, in the City of Wilmington, County
of New Castle.  The name of its registered agent at such address is The
Corporation Trust Company.

     THIRD.  The nature of the business or purposes to be conducted or promoted
by the Corporation is as follows:
<PAGE>

          To engage in any lawful act or activity for which corporations may be
     organized under the General Corporation Law of Delaware.

     FOURTH.  The total number of shares of all classes of stock which the
Corporation shall have authority to issue is 102,000,000 shares, consisting of
(i) 100,000,000 shares of Common Stock, $.001 par value per share ("Common
Stock"), and (ii) 2,000,000 shares of Preferred Stock, $.10 par value per share
("Preferred Stock").

     The following is a statement of the designations and the powers, privileges
and rights, and the qualifications, limitations or restrictions thereof in
respect of each class of capital stock of the Corporation.

A.   COMMON STOCK.
     ------------

     1.  General.  The voting, dividend and liquidation rights of the holders of
         -------
the Common Stock are subject to and qualified by the rights of the holders of
the Preferred Stock of any series as may be designated by the Board of Directors
upon any issuance of the Preferred Stock of any series.

     2.  Voting.  The holders of the Common Stock are entitled to one vote for
         ------
each share held at all meetings of stockholders (and written actions in lieu of
meetings).  There shall be no cumulative voting.

     The number of authorized shares of Common Stock may be increased or
decreased (but not below the number of shares thereof then outstanding) by the
affirmative vote of the holders of a majority of the stock of the Corporation
entitled to vote, irrespective of the provisions of Section 242(b)(2) of the
General Corporation Law of Delaware.

     3.  Dividends.  Dividends may be declared and paid on the Common Stock from
         ---------
funds lawfully available therefor as and when determined by the Board of
Directors and subject to any preferential dividend rights of any then
outstanding Preferred Stock.

     4.  Liquidation.  Upon the dissolution or liquidation of the Corporation,
         -----------
whether voluntary or involuntary, holders of Common Stock will be entitled to
receive all assets of the Corporation available for distribution to its
stockholders, subject to any preferential rights of any then outstanding
Preferred Stock.

B.   PREFERRED STOCK.
     ---------------

     Preferred Stock may be issued from time to time in one or more series, each
of such series to have such terms as stated or expressed herein and in the
resolution or resolutions providing for the issue of such series adopted by the
Board of Directors of

                                      -2-
<PAGE>

the Corporation as hereinafter provided. Any shares of Preferred Stock which may
be redeemed, purchased or acquired by the Corporation may be reissued except as
otherwise provided by law or this Certificate of Incorporation. Different series
of Preferred Stock shall not be construed to constitute different classes of
shares for the purposes of voting by classes unless expressly provided.

     Authority is hereby expressly granted to the Board of Directors from time
to time to issue the Preferred Stock in one or more series, and in connection
with the creation of any such series, by resolution or resolutions providing for
the issue of the shares thereof, to determine and fix such voting powers, full
or limited, or no voting powers, and such designations, preferences and relative
participating, optional or other special rights, and qualifications, limitations
or restrictions thereof, including without limitation thereof, dividend rights,
conversion rights, redemption privileges and liquidation preferences, as shall
be stated and expressed in such resolutions, all to the full extent now or
hereafter permitted by the General Corporation Law of Delaware.  Without
limiting the generality of the foregoing, the resolutions providing for issuance
of any series of Preferred Stock may provide that such series shall be superior
or rank equally or be junior to the Preferred Stock of any other series to the
extent permitted by law and this Certificate of Incorporation.  Except as
otherwise provided in this Certificate of Incorporation, no vote of the holders
of the Preferred Stock or Common Stock shall be a prerequisite to the
designation or issuance of any shares of any series of the Preferred Stock
authorized by and complying with the conditions of this Certificate of
Incorporation, the right to have such vote being expressly waived by all present
and future holders of the capital stock of the Corporation.

     FIFTH.   The Corporation shall have a perpetual existence.

     SIXTH.   In furtherance of and not in limitation of powers conferred by
statute, it is further provided:

          1.  Election of directors need not be by written ballot.

          2.  The Board of Directors is expressly authorized to adopt, amend or
repeal the By-Laws of the Corporation.

     SEVENTH. Whenever a compromise or arrangement is proposed between this
Corporation and its creditors or any class of them and/or between this
Corporation and its stockholders or any class of them, any court of equitable
jurisdiction within the State of Delaware may, on the application in a summary
way of this Corporation or of any creditor or stockholder thereof, or on the
application of any receiver or receivers appointed for this Corporation under
the provisions of section 291 of Title 8 of the Delaware Code or on the
application of trustees in dissolution or of any receiver or receivers appointed
for this Corporation under the provisions of section

                                      -3-
<PAGE>

279 of Title 8 of the Delaware Code order a meeting of the creditors or class of
creditors, and/or of the stockholders or class of stockholders of this
Corporation, as the case may be, to be summoned in such manner as the said court
directs. If a majority in number representing three-fourths in value of the
creditors or class of creditors, and/or of the stockholders or class of
stockholders of this Corporation, as the case may be, agree to any compromise or
arrangement and to any reorganization of this Corporation as a consequence of
such compromise or arrangement, the said compromise or arrangement and the said
reorganization shall, if sanctioned by the court to which the said application
has been made, be binding on all the creditors or class of creditors, and/or on
all the stockholders or class of stockholders, of this Corporation, as the case
may be, and also on this Corporation.

     EIGHTH.  Except to the extent that the General Corporation Law of the State
of Delaware prohibits the elimination or limitation of liability of directors
for breaches of fiduciary duty, no director of the Corporation shall be
personally liable to the Corporation or its stockholders for monetary damages
for any breach of fiduciary duty as a director, notwithstanding any provision of
law imposing such liability.  No amendment to or repeal of this provision shall
apply to or have any effect on the liability or alleged liability of any
director of the Corporation for or with respect to any acts or omissions of such
director occurring prior to such amendment.

     NINTH.   1.  Action, Suits and Proceedings Other than by or in the Right of
                  --------------------------------------------------------------
the Corporation.  The Corporation shall indemnify each person who was or is a
---------------
party or is threatened to be made a party to any threatened, pending or
completed action, suit or proceeding, whether civil, criminal, administrative or
investigative (other than an action by or in the right of the Corporation), by
reason of the fact that he is or was, or has agreed to become, a director or
officer of the Corporation, or is or was serving, or has agreed to serve, at the
request of the Corporation, as a director, officer or trustee of, or in a
similar capacity with, another corporation, partnership, joint venture, trust or
other enterprise (including any employee benefit plan) (all such persons being
referred to hereafter as an "Indemnitee"), or by reason of any action alleged to
have been taken or omitted in such capacity, against all expenses (including
attorneys' fees), judgments, fines and amounts paid in settlement actually and
reasonably incurred by him or on his behalf in connection with such action, suit
or proceeding and any appeal therefrom, if he acted in good faith and in a
manner he reasonably believed to be in, or not opposed to, the best interests of
the Corporation, and, with respect to any criminal action or proceeding, had no
reasonable cause to believe his conduct was unlawful.  The termination of any
action, suit or proceeding by judgment, order, settlement, conviction or upon a
plea of nolo contendere or its equivalent, shall not, of itself, create a
        ---- ----------
presumption that the person did not act in good faith and in a manner which he
reasonably believed to be in, or not opposed to, the best interests of the
Corporation, and, with respect to any criminal action or proceeding, had
reasonable cause to believe that his conduct was unlawful.  Notwithstanding
anything to the contrary in this Article, except as set forth in

                                      -4-
<PAGE>

Section 6 below, the Corporation shall not indemnify an Indemnitee seeking
indemnification in connection with a proceeding (or part thereof) initiated by
the Indemnitee unless the initiation thereof was approved by the Board of
Directors of the Corporation.

     2.  Actions or Suits by or in the Right of the Corporation.  The
         ------------------------------------------------------
Corporation shall indemnify any Indemnitee who was or is a party or is
threatened to be made a party to any threatened, pending or completed action or
suit by or in the right of the Corporation to procure a judgment in its favor by
reason of the fact that he is or was, or has agreed to become, a director or
officer of the Corporation, or is or was serving, or has agreed to serve, at the
request of the Corporation, as a director, officer or trustee of, or in a
similar capacity with, another corporation, partnership, joint venture, trust or
other enterprise (including any employee benefit plan), or by reason of any
action alleged to have been taken or omitted in such capacity, against all
expenses (including attorneys' fees) and amounts paid in settlement actually and
reasonably incurred by him or on his behalf in connection with such action, suit
or proceeding and any appeal therefrom, if he acted in good faith and in a
manner he reasonably believed to be in, or not opposed to, the best interests of
the Corporation, except that no indemnification shall be made in respect of any
claim, issue or matter as to which such person shall have been adjudged to be
liable to the Corporation unless and only to the extent that the Court of
Chancery of Delaware or the court in which such action or suit was brought shall
determine upon application that, despite the adjudication of such liability but
in view of all the circumstances of the case, such person is fairly and
reasonably entitled to indemnity for such expenses (including attorneys' fees)
which the Court of Chancery of Delaware or such other court shall deem proper.

     3.  Indemnification for Expenses of Successful Party.  Notwithstanding the
         ------------------------------------------------
other provisions of this Article, to the extent that an Indemnitee has been
successful, on the merits or otherwise, in defense of any action, suit or
proceeding referred to in Sections 1 and 2 of this Article, or in defense of any
claim, issue or matter therein, or on appeal from any such action, suit or
proceeding, he shall be indemnified against all expenses (including attorneys'
fees) actually and reasonably incurred by him or on his behalf in connection
therewith.  Without limiting the foregoing, if any action, suit or proceeding is
disposed of, on the merits or otherwise (including a disposition without
prejudice), without (i) the disposition being adverse to the Indemnitee, (ii) an
adjudication that the Indemnitee was liable to the Corporation, (iii) a plea of
guilty or nolo contendere by the Indemnitee, (iv) an adjudication that the
          ---- ----------
Indemnitee did not act in good faith and in a manner he reasonably believed to
be in or not opposed to the best interests of the Corporation, and (v) with
respect to any criminal proceeding, an adjudication that the Indemnitee had
reasonable cause to believe his conduct was unlawful, the Indemnitee shall be
considered for the purposes hereof to have been wholly successful with respect
thereto.

                                      -5-
<PAGE>

     4.  Notification and Defense of Claim.  As a condition precedent to his
         ---------------------------------
right to be indemnified, the Indemnitee must notify the Corporation in writing
as soon as practicable of any action, suit, proceeding or investigation
involving him for which indemnity will or could be sought.  With respect to any
action, suit, proceeding or investigation of which the Corporation is so
notified, the Corporation will be entitled to participate therein at its own
expense and/or to assume the defense thereof at its own expense, with legal
counsel reasonably acceptable to the Indemnitee.  After notice from the
Corporation to the Indemnitee of its election so to assume such defense, the
Corporation shall not be liable to the Indemnitee for any legal or other
expenses subsequently incurred by the Indemnitee in connection with such claim,
other than as provided below in this Section 4.  The Indemnitee shall have the
right to employ his own counsel in connection with such claim, but the fees and
expenses of such counsel incurred after notice from the Corporation of its
assumption of the defense thereof shall be at the expense of the Indemnitee
unless (i) the employment of counsel by the Indemnitee has been authorized by
the Corporation, (ii) counsel to the Indemnitee shall have reasonably concluded
that there may be a conflict of interest or position on any significant issue
between the Corporation and the Indemnitee in the conduct of the defense of such
action or (iii) the Corporation shall not in fact have employed counsel to
assume the defense of such action, in each of which cases the fees and expenses
of counsel for the Indemnitee shall be at the expense of the Corporation, except
as otherwise expressly provided by this Article.  The Corporation shall not be
entitled, without the consent of the Indemnitee, to assume the defense of any
claim brought by or in the right of the Corporation or as to which counsel for
the Indemnitee shall have reasonably made the conclusion provided for in clause
(ii) above.

     5.  Advance of Expenses.  Subject to the provisions of Section 6 below, in
         -------------------
the event that the Corporation does not assume the defense pursuant to Section 4
of this Article of any action, suit, proceeding or investigation of which the
Corporation receives notice under this Article, any expenses (including
attorneys' fees) incurred by an Indemnitee in defending a civil or criminal
action, suit, proceeding or investigation or any appeal therefrom shall be paid
by the Corporation in advance of the final disposition of such matter; provided,
                                                                       --------
however, that the payment of such expense incurred by an Indemnitee in advance
-------
of the final disposition of such matter shall be made only upon receipt of an
undertaking by or on behalf of the Indemnitee to repay all amounts so advanced
in the event that it shall ultimately be determined that the Indemnitee is not
entitled to be indemnified by the Corporation as authorized in this Article.
Such undertaking may be accepted without reference to the financial ability of
the Indemnitee to make such repayment.

     6.  Procedure for Indemnification.  In order to obtain indemnification or
         -----------------------------
advancement of expenses pursuant to Section 1, 2, 3 or 5 of this Article, the
Indemnitee shall submit to the Corporation a written request, including in such
request such documentation and information as is reasonably available to the

                                      -6-
<PAGE>

Indemnitee and is reasonably necessary to determine whether and to what extent
the Indemnitee is entitled to indemnification or advancement of expenses.  Any
such indemnification or advancement of expenses shall be made promptly, and in
any event within 60 days after receipt by the Corporation of the written request
of the Indemnitee, unless with respect to requests under Section 1, 2 or 5 the
Corporation determines, by clear and convincing evidence, within such 60-day
period that the Indemnitee did not meet the applicable standard of conduct set
forth in Section 1 or 2, as the case may be.  Such determination shall be made
in each instance by (a) a majority vote of a quorum of the directors of the
Corporation consisting of persons who are not at that time parties to the
action, suit or proceeding in question ("disinterested directors"), (b) if no
such quorum is obtainable, a majority vote of a committee of two or more
disinterested directors, (c) a majority vote of a quorum of the outstanding
shares of stock of all classes entitled to vote for directors, voting as a
single class, which quorum shall consist of stockholders who are not at that
time parties to the action, suit or proceeding in question, (d) independent
legal counsel (who may be regular legal counsel to the Corporation), or (e) a
court of competent jurisdiction.

     7.  Remedies.  The right to indemnification or advances as granted by this
         --------
Article shall be enforceable by the Indemnitee in any court of competent
jurisdiction if the Corporation denies such request, in whole or in part, or if
no disposition thereof is made within the 60-day period referred to above in
Section 6.  Unless otherwise provided by law, the burden of proving that the
Indemnitee is not entitled to indemnification or advance of expenses under this
Article shall be on the Corporation.  Neither the failure of the Corporation to
have made a determination prior to the commencement of such action that
indemnification is proper in the circumstances because the Indemnitee has met
the applicable standard of conduct, nor an actual determination by the
Corporation pursuant to Section 6 that the Indemnitee has not met such
applicable standard of conduct, shall be a defense to the action or create a
presumption that the Indemnitee has not met the applicable standard of conduct.
The Indemnitee's expenses (including attorneys' fees) incurred in connection
with successfully establishing his right to indemnification, in whole or in
part, in any such proceeding shall also be indemnified by the Corporation.

     8.  Subsequent Amendment.  No amendment, termination or repeal of this
         --------------------
Article or of the relevant provisions of the General Corporation Law of Delaware
or any other applicable laws shall affect or diminish in any way the rights of
any Indemnitee to indemnification under the provisions hereof with respect to
any action, suit, proceeding or investigation arising out of or relating to any
actions, transactions or facts occurring prior to the final adoption of such
amendment, termination or repeal.

     9.  Other Rights.  The indemnification and advancement of expenses provided
         ------------
by this Article shall not be deemed exclusive of any other rights to which

                                      -7-
<PAGE>

an Indemnitee seeking indemnification or advancement of expenses may be
entitled under any law (common or statutory), agreement or vote of
stockholders or disinterested directors or otherwise, both as to action in his
official capacity and as to action in any other capacity while holding office
for the Corporation, and shall continue as to an Indemnitee who has ceased
to be a director or officer, and shall inure to the benefit of the estate,
heirs, executors and administrators of the Indemnitee. Nothing contained
in this Article shall be deemed to prohibit, and the Corporation is
specifically authorized to enter into, agreements with officers and directors
providing indemnification rights and procedures different from those set forth
in this Article. In addition, the Corporation may, to the extent authorized
from time to time by its Board of Directors, grant indemnification rights
to other employees or agents of the Corporation or other persons serving
the Corporation and such rights may be equivalent to, or greater or less
than, those set forth in this Article.

     10.  Partial Indemnification.  If an Indemnitee is entitled under any
          -----------------------
provision of this Article to indemnification by the Corporation for some or a
portion of the expenses (including attorneys' fees), judgments, fines or amounts
paid in settlement actually and reasonably incurred by him or on his behalf in
connection with any action, suit, proceeding or investigation and any appeal,
therefrom but not, however, for the total amount thereof, the Corporation shall
nevertheless indemnify the Indemnitee for the portion of such expenses
(including attorneys' fees), judgments, fines or amounts paid in settlement to
which the Indemnitee is entitled.

     11.  Insurance.  The Corporation may purchase and maintain insurance, at
          ---------
its expense, to protect itself and any director, officer, employee or agent of
the Corporation or another corporation, partnership, joint venture, trust or
other enterprise (including any employee benefit plan) against any expense,
liability or loss incurred by him in any such capacity, or arising out of his
status as such, whether or not the Corporation would have the power to indemnify
such person against such expense, liability or loss under the General
Corporation Law of Delaware.

     12.  Merger or Consolidation.  If the Corporation is merged into or
          -----------------------
consolidated with another corporation and the Corporation is not the surviving
corporation, the surviving corporation shall assume the obligations of the
Corporation under this Article with respect to any action, suit, proceeding or
investigation arising out of or relating to any actions, transactions or facts
occurring prior to the date of such merger or consolidation.

     13.  Savings Clause.  If this Article or any portion hereof shall be
          --------------
invalidated on any ground by any court of competent jurisdiction, then the
Corporation shall nevertheless indemnify each Indemnitee as to any expenses
(including attorneys' fees), judgments, fines and amounts paid in settlement in
connection with any action, suit, proceeding or investigation, whether civil,
criminal or administrative, including

                                      -8-
<PAGE>

an action by or in the right of the Corporation, to the fullest extent permitted
by any applicable portion of this Article that shall not have been invalidated
and to the fullest extent permitted by applicable law.

     14.  Definitions.  Terms used herein and defined in Section 145(h) and
          -----------
Section 145(i) of the General Corporation Law of Delaware shall have the
respective meanings assigned to such terms in such Section 145(h) and Section
145(i).

     15.  Subsequent Legislation.  If the General Corporation Law of Delaware is
          ----------------------
amended after adoption of this Article to expand further the indemnification
permitted to Indemnitees, then the Corporation shall indemnify such persons to
the fullest extent permitted by the General Corporation Law of Delaware, as so
amended.

     TENTH.  The Corporation reserves the right to amend, alter, change or
repeal any provision contained in this Amended and Restated Certificate of
Incorporation, in the manner now or hereafter prescribed by statute and this
Amended and Restated Certificate of Incorporation, and all rights conferred upon
stockholders herein are granted subject to this reservation.

     ELEVENTH.  This Article is inserted for the management of the business and
for the conduct of the affairs of the Corporation.

     1.   Number of Directors,  The number of directors of the Corporation shall
          -------------------
not be less than three.  The exact number of directors within the limitations
specified in the preceding sentence shall be fixed from time to time by, or in
the manner provided in, the Corporation's By-Laws.

     2.   Classes of Directors.  The Board of Directors shall be and is divided
          --------------------
into three classes:  Class I, Class II and Class III.  No one class shall have
more than one director more than any other class.  If a fraction is contained in
the quotient arrived at by dividing the designated number of directors by three,
then, if such fraction is one-third, the extra director shall be a member of
Class I, and if such fraction is two-thirds, one of the extra directors shall be
a member of Class I and one of the extra directors shall be a member of Class
II, unless otherwise provided from time to time by resolution adopted by the
Board of Directors.

     3.   Election of Directors.  Elections of directors need not be by written
          ---------------------
ballot except as and to the extent provided in the By-Laws of the Corporation.

     4.   Terms of Office.  Each director shall serve for a term ending on the
          ---------------
date of the third annual meeting following the annual meeting at which such
director was elected; provided, that each initial director in Class I shall
                      --------
serve for a term ending on the date of the annual meeting in 1997; each initial
director in Class II shall serve for a term ending on the date of the annual
meeting in 1998; and each initial director in

                                      -9-
<PAGE>

Class III shall serve for a term ending on the date of the annual meeting in
1999; and provided further, that the term of each director shall be subject to
          ----------------
the election and qualification of his successor and to his earlier death,
resignation or removal.

     5.  Allocation of Directors Among Classes in the Event of Increases or
         ------------------------------------------------------------------
Decreases in the Number of Directors.  In the event of any increase or decrease
------------------------------------
in the authorized number of directors, (i) each director then serving as such
shall nevertheless continue as a director of the class of which he is a member
and (ii) the newly created or eliminated directorships resulting from such
increase or decrease shall be apportioned by the Board of Directors among the
three classes of directors so as to ensure that no one class has more than one
director more than any other class.   To the extent possible, consistent with
the foregoing rule, any newly created directorships shall be added to those
classes whose terms of office are to expire at the latest dates following such
allocation, and any newly eliminated directorships shall be subtracted from
those classes whose terms of offices are to expire at the earliest dates
following such allocation, unless otherwise provided from time to time by
resolution adopted by the Board of Directors.

     6.  Quorum; Action at Meeting.  A majority of the directors at any time in
         -------------------------
office shall constitute a quorum for the transaction of business.  In the event
one or more of the directors shall be disqualified to vote at any meeting, then
the required quorum shall be reduced by one for each director so disqualified,
provided that in no case shall less than one-third of the number of directors
fixed pursuant to Section 1 above constitute a quorum.  If at any meeting of the
Board of Directors there shall be less than such a quorum, a majority of those
present may adjourn the meeting from time to time.  Every act or decision done
or made by a majority of the directors present at a meeting duly held at which a
quorum is present shall be regarded as the act of the Board of Directors unless
a greater number is required by law, by the By-Laws of the Corporation or by
this Amended and Restated Certificate of Incorporation.

     7.  Removal.  Directors of the Corporation may be removed only for cause by
         -------
the affirmative vote of the holders of at least two-thirds of the shares of the
capital stock of the Corporation issued and outstanding and entitled to vote.

     8.  Vacancies.  Any vacancy in the Board of Directors, however occurring,
         ---------
including a vacancy resulting from an enlargement of the board, shall be filled
only by a vote of a majority of the directors then in office, although less than
a quorum, or by a sole remaining director.  A director elected to fill a vacancy
shall be elected to hold office until the next election of the class for which
such director shall have been chosen, subject to the election and qualification
of his successor and to his earlier death, resignation or removal.

                                      -10-
<PAGE>

     9.   Stockholder Nominations and Introduction of Business, Etc.  Advance
          ----------------------------------------------------------
notice of stockholder nominations for election of directors and other business
to be brought by stockholders before a meeting of stockholders shall be given in
the manner provided by the By-Laws of the Corporation.

     10.  Amendments to Article.  Notwithstanding any other provisions of law,
          ---------------------
this Amended and Restated Certificate of Incorporation or the By-Laws of the
Corporation, each as amended, and notwithstanding the fact that a lesser
percentage may be specified by law, the affirmative vote of the holders of at
least seventy-five percent (75%) of the shares of capital stock of the
Corporation issued and outstanding and entitled to vote shall be required to
amend or repeal, or to adopt any provision inconsistent with, this Article
ELEVENTH.

     TWELFTH.  Stockholders of the Corporation may not take any action by
written consent in lieu of a meeting.  Notwithstanding any other provisions of
law, the Amended and Restated Certificate of Incorporation or the By-Laws of the
Corporation, each as amended, and notwithstanding the fact that a lesser
percentage may be specified by law, the affirmative vote of the holders of at
least seventy-five percent (75%) of the shares of capital stock of the
Corporation issued and outstanding and entitled to vote shall be required to
amend or repeal, or to adopt any provision inconsistent with, this Article
TWELFTH.

     THIRTEENTH.  Special meetings of stockholders may be called at any time by
only the Chairman of the Board of Directors, the Chief Executive Officer (or if
there is no Chief Executive Officer, the President) or the Board of Directors.
Business transacted at any special meeting of stockholders shall be limited to
matters relating to the purpose or purposes stated in the notice of meeting.
Notwithstanding any other provision of law, this Amended and Restated
Certificate of Incorporation or the By-Laws of the Corporation, each as amended,
and notwithstanding the fact that a lesser percentage may be specified by law,
the affirmative vote of the holders of at least seventy-five percent (75%) of
the shares of capital stock of the Corporation issued and outstanding and
entitled to vote shall be required to amend or repeal, or to adopt any provision
inconsistent with, this Article THIRTEENTH.

                                      -11-
<PAGE>

     IN WITNESS WHEREOF, the Corporation has caused its corporate seal to be
affixed hereto and this Amended and Restated Certificate of Incorporation to be
signed by its Chief Executive Officer this 28th day of May, 1996.


                              OPEN MARKET, INC.


                              By:    /s/ Gary B. Eichhorn
                                   -----------------------------------------
                                    Gary B. Eichhorn
                                    Chief Executive Officer

                                     -12-
<PAGE>

                          CERTIFICATE OF DESIGNATIONS

                                      of

                               OPEN MARKET, INC.

                        (Pursuant to Section 151 of the
                       Delaware General Corporation Law)


                        ______________________________


     Open Market, Inc., a corporation organized and existing under the General
Corporation Law of the State of Delaware (hereinafter called the "Corporation"),
hereby certifies that the following resolution was adopted by the Board of
Directors of the Corporation as required by Section 151 of the General
Corporation Law at a meeting duly called and held on January 23, 1998:

     RESOLVED, that pursuant to the authority granted to and vested in the Board
of Directors of this Corporation (hereinafter called the "Board of Directors" or
the "Board") in accordance with the provisions of the Certificate of
Incorporation, the Board of Directors hereby creates a series of Preferred
Stock, $.10 par value (the "Preferred Stock"), of the Corporation and hereby
states the designation and number of shares, and fixes the relative rights,
preferences and limitations thereof as follows:

     Series A Junior Participating Preferred Stock:

     Section 1.  Designation and Amount.  The shares of such series shall be
                 ----------------------
designated as "Series A Junior Participating Preferred Stock" (the "Series A
Preferred Stock") and the number of shares constituting the Series A Preferred
Stock shall be 40,000.  Such number of shares may be increased or decreased by
resolution of the Board of Directors; provided, that no decrease shall reduce
                                      --------
the number of shares of Series A Preferred Stock to a number less than the
number of shares then outstanding plus the number of shares reserved for
issuance upon the exercise of outstanding options, rights or warrants or upon
the conversion of any outstanding securities issued by the Corporation
convertible into Series A Preferred Stock.

     Section 2.  Dividends and Distributions.
                 ---------------------------

                    (A) Subject to the rights of the holders of any shares of
any series of Preferred Stock (or any similar stock) ranking prior and superior
to the Series A Preferred Stock with respect to dividends, the holders of shares
of Series A Preferred Stock, in preference to the holders of Common Stock, par
value $.01 per share (the "Common Stock"), of the Corporation, and of any other
junior stock, shall
<PAGE>

be entitled to receive, when, as and if declared by the Board of Directors out
of funds of the Corporation legally available for the payment of dividends,
quarterly dividends payable in cash on March 31, June 30, September 30 and
December 31 in each year (each such date being referred to herein as a
"Quarterly Dividend Payment Date"), commencing on the first Quarterly Dividend
Payment Date after the first issuance of a share or fraction of a share of
Series A Preferred Stock, in an amount per share (rounded to the nearest cent)
equal to the greater of (a) $100 or (b) subject to the provision for adjustment
hereinafter set forth, 1,000 times the aggregate per share amount of all cash
dividends, and 1,000 times the aggregate per share amount (payable in kind) of
all non-cash dividends or other distributions, other than a dividend payable in
shares of Common Stock or a subdivision of the outstanding shares of Common
Stock (by reclassification or otherwise), declared on the Common Stock since the
immediately preceding Quarterly Dividend Payment Date or, with respect to the
first Quarterly Dividend Payment Date, since the first issuance of any share or
fraction of a share of Series A Preferred Stock. In the event the Corporation
shall at any time declare or pay any dividend on the Common Stock payable in
shares of Common Stock, or effect a subdivision, combination or consolidation of
the outstanding shares of Common Stock (by reclassification or otherwise than by
payment of a dividend in shares of Common Stock) into a greater or lesser number
of shares of Common Stock, then in each such case the amount to which holders of
shares of Series A Preferred Stock were entitled immediately prior to such event
under clause (b) of the preceding sentence shall be adjusted by multiplying such
amount by a fraction, the numerator of which is the number of shares of Common
Stock outstanding immediately after such event and the denominator of which is
the number of shares of Common Stock that were outstanding immediately prior to
such event. In the event the Corporation shall at any time declare or pay any
dividend on the Series A Preferred Stock payable in shares of Series A Preferred
Stock, or effect a subdivision, combination or consolidation of the outstanding
shares of Series A Preferred Stock (by reclassification or otherwise than by
payment of a dividend in shares of Series A Preferred Stock) into a greater or
lesser number of shares of Series A Preferred Stock, then in each such case the
amount to which holders of shares of Series A Preferred Stock were entitled
immediately prior to such event under clause (b) of the first sentence of this
Section 2(A) shall be adjusted by multiplying such amount by a fraction, the
numerator of which is the number of shares of Series A Preferred Stock that were
outstanding immediately prior to such event and the denominator of which is the
number of shares of Series A Preferred Stock outstanding immediately after such
event.

          (B) The Corporation shall declare a dividend or distribution on the
Series A Preferred Stock as provided in paragraph (A) of this Section
immediately after it declares a dividend or distribution on the Common Stock
(other than a dividend payable in shares of Common Stock) and the Corporation
shall pay such dividend or distribution on the Series A Preferred Stock before
the dividend or distribution declared on the Common Stock is paid or set apart;
provided that, in the

                                      -2-
<PAGE>

event no dividend or distribution shall have been declared on the Common Stock
during the period between any Quarterly Dividend Payment Date and the next
subsequent Quarterly Dividend Payment Date, a dividend of $100 per share on the
Series A Preferred Stock shall nevertheless be payable on such subsequent
Quarterly Dividend Payment Date.

                    (C) Dividends shall begin to accrue and be cumulative on
outstanding shares of Series A Preferred Stock from the Quarterly Dividend
Payment Date next preceding the date of issue of such shares, unless the date of
issue of such shares is prior to the record date for the first Quarterly
Dividend Payment Date, in which case dividends on such shares shall begin to
accrue from the date of issue of such shares, or unless the date of issue is a
Quarterly Dividend Payment Date or is a date after the record date for the
determination of holders of shares of Series A Preferred Stock entitled to
receive a quarterly dividend and before such Quarterly Dividend Payment Date, in
either of which events such dividends shall begin to accrue and be cumulative
from such Quarterly Dividend Payment Date. Accrued but unpaid dividends shall
not bear interest. Dividends paid on the shares of Series A Preferred Stock in
an amount less than the total amount of such dividends at the time accrued and
payable on such shares shall be allocated pro rata on a share-by-share basis
among all such shares at the time outstanding. The Board of Directors may fix a
record date for the determination of holders of shares of Series A Preferred
Stock entitled to receive payment of a dividend or distribution declared
thereon, which record date shall be not more than 60 days prior to the date
fixed for the payment thereof.

     Section 3.  Voting Rights.  The holders of shares of Series A Preferred
                 -------------
Stock shall have the following voting rights:

                    (A) Subject to the provision for adjustment hereinafter set
forth, each share of Series A Preferred Stock shall entitle the holder thereof
to 1,000 votes on all matters submitted to a vote of the stockholders of the
Corporation. In the event the Corporation shall at any time declare or pay any
dividend on the Common Stock payable in shares of Common Stock, or effect a
subdivision, combination or consolidation of the outstanding shares of Common
Stock (by reclassification or otherwise than by payment of a dividend in shares
of Common Stock) into a greater or lesser number of shares of Common Stock, then
in each such case the number of votes per share to which holders of shares of
Series A Preferred Stock were entitled immediately prior to such event shall be
adjusted by multiplying such number by a fraction, the numerator of which is the
number of shares of Common Stock outstanding immediately after such event and
the denominator of which is the number of shares of Common Stock that were
outstanding immediately prior to such event. In the event the Corporation shall
at any time declare or pay any dividend on the Series A Preferred Stock payable
in shares of Series A Preferred Stock, or effect a subdivision, combination or
consolidation of the outstanding shares

                                      -3-
<PAGE>

of Series A Preferred Stock (by reclassification or otherwise than by payment of
a dividend in shares of Series A Preferred Stock) into a greater or lesser
number of shares of Series A Preferred Stock, then in each such case the number
of votes per share to which holders of shares of Series A Preferred Stock were
entitled immediately prior to such event shall be adjusted by multiplying such
amount by a fraction, the numerator of which is the number of shares of Series A
Preferred Stock that were outstanding immediately prior to such event and the
denominator of which is the number of shares of Series A Preferred Stock
outstanding immediately after such event.

          (B) Except as otherwise provided herein, in the Certificate of
Incorporation or by law, the holders of shares of Series A Preferred Stock and
the holders of shares of Common Stock and any other capital stock of the
Corporation having general voting rights shall vote together as one class on all
matters submitted to a vote of stockholders of the Corporation.

          (C)(i) If at any time dividends on any Series A Preferred Stock shall
be in arrears in an amount equal to six quarterly dividends thereon, the holders
of the Series A Preferred Stock, voting as a separate series from all other
series of Preferred Stock and classes of capital stock, shall be entitled to
elect two members of the Board of Directors in addition to any Directors elected
by any other series, class or classes of securities and the authorized number of
Directors will automatically be increased by two.  Promptly thereafter, the
Board of Directors of this Corporation shall, as soon as may be practicable,
call a special meeting of holders of Series A Preferred Stock for the purpose of
electing such members of the Board of Directors.  Said special meeting shall in
any event be held within 45 days of the occurrence of such arrearage.

          (ii)  During any period when the holders of Series A Preferred Stock,
voting as a separate series, shall be entitled and shall have exercised their
right to elect two Directors, then and during such time as such right continues
(a) the then authorized number of Directors shall be increased by two, and the
holders of Series A Preferred Stock, voting as a separate series, shall be
entitled to elect the additional Directors so provided for, and (b) each such
additional Director shall not be a member of any existing class of the Board of
Directors, but shall serve until the next annual meeting of stockholders for the
election of Directors, or until his successor shall be elected and shall
qualify, or until his right to hold such office terminates pursuant to the
provisions of this Section 3(C).

          (iii) A Director elected pursuant to the terms hereof may be removed
with or without cause by the holders of Series A Preferred Stock entitled to
vote in an election of such Director.

                                      -4-
<PAGE>

               (iv) If, during any interval between annual meetings of
stockholders for the election of Directors and while the holders of Series A
Preferred Stock shall be entitled to elect two Directors, there is no such
Director in office by reason of resignation, death or removal, then, promptly
thereafter, the Board of Directors shall call a special meeting of the holders
of Series A Preferred Stock for the purpose of filling such vacancy and such
vacancy shall be filled at such special meeting. Such special meeting shall in
any event be held within 45 days of the occurrence of such vacancy.

               (v)  At such time as the arrearage is fully cured, and all
dividends accumulated and unpaid on any shares of Series A Preferred Stock
outstanding are paid, and, in addition thereto, at least one regular dividend
has been paid subsequent to curing such arrearage, the term of office of any
Director elected pursuant to this Section 3(C), or his successor, shall
automatically terminate, and the authorized number of Directors shall
automatically decrease by two, the rights of the holders of the shares of the
Series A Preferred Stock to vote as provided in this Section 3(C) shall cease,
subject to renewal from time to time upon the same terms and conditions, and the
holders of shares of the Series A Preferred Stock shall have only the limited
voting rights elsewhere herein set forth.

          (D)  Except as set forth herein, or as otherwise provided by law,
holders of Series A Preferred Stock shall have no special voting rights and
their consent shall not be required (except to the extent they are entitled to
vote with holders of Common Stock as set forth herein) for taking any corporate
action.

     Section 4.  Certain Restrictions.
                 --------------------

          (A)  Whenever quarterly dividends or other dividends or distributions
payable on the Series A Preferred Stock as provided in Section 2 are in arrears,
thereafter and until all accrued and unpaid dividends and distributions, whether
or not declared, on shares of Series A Preferred Stock outstanding shall have
been paid in full, the Corporation shall not:

               (i)  declare or pay dividends, or make any other distributions,
     on any shares of stock ranking junior (either as to dividends or upon
     liquidation, dissolution or winding up) to the Series A Preferred Stock;

               (ii) declare or pay dividends, or make any other distributions,
     on any shares of stock ranking on a parity (either as to dividends or upon
     liquidation, dissolution or winding up) with the Series A Preferred Stock,
     except dividends paid ratably on the Series A Preferred Stock and all such
     parity stock on which dividends are payable or in arrears in proportion to
     the total amounts to which the holders of all such shares are then
     entitled;

                                      -5-
<PAGE>

               (iii) redeem or purchase or otherwise acquire for consideration
     shares of any stock ranking junior (either as to dividends or upon
     liquidation, dissolution or winding up) to the Series A Preferred Stock,
     provided that the Corporation may at any time redeem, purchase or otherwise
     acquire shares of any such junior stock in exchange for shares of any stock
     of the Corporation ranking junior (either as to dividends or upon
     dissolution, liquidation or winding up) to the Series A Preferred Stock; or

               (iv)  redeem or purchase or otherwise acquire for consideration
     any shares of Series A Preferred Stock, or any shares of stock ranking on a
     parity with the Series A Preferred Stock, except in accordance with a
     purchase offer made in writing or by publication (as determined by the
     Board of Directors) to all holders of such shares upon such terms as the
     Board of Directors, after consideration of the respective annual dividend
     rates and other relative rights and preferences of the respective series
     and classes, shall determine in good faith will result in fair and
     equitable treatment among the respective series or classes.

               (B)   The Corporation shall not permit any subsidiary of the
Corporation to purchase or otherwise acquire for consideration any shares of
stock of the Corporation unless the Corporation could, under paragraph (A) of
this Section 4, purchase or otherwise acquire such shares at such time and in
such manner.

     Section 5.  Reacquired Shares.  Any shares of Series A Preferred Stock
                 -----------------
purchased or otherwise acquired by the Corporation in any manner whatsoever
shall be retired and cancelled promptly after the acquisition thereof.  All such
shares shall upon their cancellation become authorized but unissued shares of
Preferred Stock and may be reissued as part of a new series of Preferred Stock
subject to the conditions and restrictions on issuance set forth herein, in the
Certificate of Incorporation, or in any other Certificate of Designations
creating a series of Preferred Stock or any similar stock or as otherwise
required by law.

     Section 6.  Liquidation, Dissolution or Winding Up.
                 --------------------------------------

               (A)   Upon any liquidation, dissolution or winding up of the
Corporation, no distribution shall be made (1) to the holders of shares of stock
ranking junior (either as to dividends or upon liquidation, dissolution or
winding up) to the Series A Preferred Stock unless, prior thereto, the holders
of shares of Series A Preferred Stock shall have received $100 per share, plus
an amount equal to accrued and unpaid dividends and distributions thereon,
whether or not declared, to the date of such payment, provided that the holders
of shares of Series A Preferred Stock shall be entitled to receive an aggregate
amount per share, subject to the provision for adjustment hereinafter set forth,
equal to 1,000 times the aggregate amount to be distributed per share to holders
of shares of Common Stock, or (2) to the holders of

                                      -6-
<PAGE>

shares of stock ranking on a parity (either as to dividends or upon liquidation,
dissolution or winding up) with the Series A Preferred Stock, except
distributions made ratably on the Series A Preferred Stock and all such parity
stock in proportion to the total amounts to which the holders of all such shares
are entitled upon such liquidation, dissolution or winding up.

          (B) Neither the consolidation, merger or other business combination of
the Corporation with or into any other corporation nor the sale, lease, exchange
or conveyance of all or any part of the property, assets or business of the
Corporation shall be deemed to be a liquidation, dissolution or winding up of
the Corporation for purposes of this Section 6.

          (C) In the event the Corporation shall at any time declare or pay any
dividend on the Common Stock payable in shares of Common Stock, or effect a
subdivision, combination or consolidation of the outstanding shares of Common
Stock (by reclassification or otherwise than by payment of a dividend in shares
of Common Stock) into a greater or lesser number of shares of Common Stock, then
in each such case the aggregate amount to which holders of shares of Series A
Preferred Stock were entitled immediately prior to such event under the proviso
in clause (1) of paragraph (A) of this Section 6 shall be adjusted by
multiplying such amount by a fraction the numerator of which is the number of
shares of Common Stock outstanding immediately after such event and the
denominator of which is the number of shares of Common Stock that were
outstanding immediately prior to such event.  In the event the Corporation shall
at any time declare or pay any dividend on the Series A Preferred Stock payable
in shares of Series A Preferred Stock, or effect a subdivision, combination or
consolidation of the outstanding shares of Series A Preferred Stock (by
reclassification or otherwise than by payment of a dividend in shares of Series
A Preferred Stock) into a greater or lesser number of shares of Series A
Preferred Stock, then in each such case the aggregate amount to which holders of
shares of Series A Preferred Stock were entitled immediately prior to such event
under the proviso in clause (1) of paragraph (A) of this Section 4 shall be
adjusted by multiplying such amount by a fraction, the numerator of which is the
number of shares of Series A Preferred Stock that were outstanding immediately
prior to such event and the denominator of which is the number of shares of
Series A Preferred Stock outstanding immediately after such event.

     Section 7.  Consolidation, Merger, etc.  Notwithstanding anything to the
                 ---------------------------
contrary contained herein, in case the Corporation shall enter into any
consolidation, merger, combination or other transaction in which the shares of
Common Stock are exchanged for or changed into other stock or securities, cash
and/or any other property, then in any such case each share of Series A
Preferred Stock shall at the same time be similarly exchanged or changed into an
amount per share, subject to the provision for adjustment hereinafter set forth,
equal to 1,000 times the aggregate amount of stock, securities, cash and/or any
other property (payable in kind), as the

                                      -7-
<PAGE>

case may be, into which or for which each share of Common Stock is changed or
exchanged. In the event the Corporation shall at any time declare or pay any
dividend on the Common Stock payable in shares of Common Stock, or effect a
subdivision, combination or consolidation of the outstanding shares of Common
Stock (by reclassification or otherwise than by payment of a dividend in shares
of Common Stock) into a greater or lesser number of shares of Common Stock, then
in each such case the amount set forth in the preceding sentence with respect to
the exchange or change of shares of Series A Preferred Stock shall be adjusted
by multiplying such amount by a fraction, the numerator of which is the number
of shares of Common Stock outstanding immediately after such event and the
denominator of which is the number of shares of Common Stock that were
outstanding immediately prior to such event. In the event the Corporation shall
at any time declare or pay any dividend on the Series A Preferred Stock payable
in shares of Series A Preferred Stock, or effect a subdivision, combination or
consolidation of the outstanding shares of Series A Preferred Stock (by
reclassification or otherwise than by payment of a dividend in shares of Series
A Preferred Stock) into a greater or lesser number of shares of Series A
Preferred Stock, then in each such case the amount set forth in the first
sentence of this Section 7 with respect to the exchange or change of shares of
Series A Preferred Stock shall be adjusted by multiplying such amount by a
fraction, the numerator of which is the number of shares of Series A Preferred
Stock that were outstanding immediately prior to such event and the denominator
of which is the number of shares of Series A Preferred Stock outstanding
immediately after such event.

     Section 8.  No Redemption.  The shares of Series A Preferred Stock shall
                 -------------
not be redeemable.

     Section 9.  Rank.  The Series A Preferred Stock shall rank, with respect to
                 ----
the payment of dividends and the distribution of assets, junior to all series of
any other class of the Preferred Stock issued either before or after the
issuance of the Series A Preferred Stock, unless the terms of any such series
shall provide otherwise.

     Section 10. Amendment.  The Certificate of Incorporation of the
                 ---------
Corporation shall not be amended in any manner which would materially alter or
change the powers, preferences or special rights of the Series A Preferred Stock
so as to affect them adversely without the affirmative vote of the holders of at
least two-thirds of the outstanding shares of Series A Preferred Stock, voting
together as a single class.

     Section 11. Fractional Shares.  Series A Preferred Stock may be issued in
                 -----------------
fractions of a share which shall entitle the holder, in proportion to such
holder's fractional shares, to exercise voting rights, receive dividends,
participate in distributions and have the benefit of all other rights of holders
of Series A Preferred Stock.

                                      -8-
<PAGE>

     IN WITNESS WHEREOF, this Certificate of Designations is executed on behalf
of the Corporation by its Chairman of the Board and Chief Executive Officer this
23rd day of January, 1998.


                                    OPEN MARKET, INC.


                                       /s/ Gary B. Eichhorn
                                    --------------------------------------------
                                    Gary B. Eichhorn
                                    President and Chief Executive Officer

                                      -9-