ZERO COUPON CONVERTIBLE PROMISSORY NOTE
                    ---------------------------------------
                                       
THIS NOTE HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED
(THE "ACT"), AND MAY NOT BE RESOLD OR OTHERWISE TRANSFERRED EXCEPT PURSUANT TO A
REGISTRATION STATEMENT WHICH HAS BEEN DECLARED EFFECTIVE UNDER THE ACT OR AN
AVAILABLE EXEMPTION FROM SUCH REGISTRATION REQUIREMENT.  FOR PURPOSES OF THE
INTERNAL REVENUE CODE OF 1986, AS AMENDED, THIS NOTE HAS BEEN ISSUED WITH
"ORIGINAL ISSUE DISCOUNT" AND THE DATE OF ORIGINAL ISSUE OF THIS NOTE IS MARCH
19, 1999.

                                 EARTHWEB INC.

                    Zero Coupon Convertible Promissory Note

                                                              New York, New York


                                                                  March 19, 1999


     EARTHWEB INC., a Delaware corporation (the "Company"), for value received,
promises to pay, subject to the terms and conditions of this Note, to DOUG
ANDERSON (the "Holder"), the sum of TWO MILLION FOUR HUNDRED THIRTY SEVEN
THOUSAND ONE HUNDRED TWENTY TWO DOLLARS AND THIRTY ONE CENTS ($2,437,122.31),
which amount includes interest, on March 21, 2000 (the "Maturity Date").

     This Note is issued by the Company pursuant to the Securities Purchase
Agreement, dated as of March 12, 1999, by and among the Company, MicroHouse
International, Inc. and Steve Anderson, Doug Anderson and Robert Anderson (the
"Purchase Agreement"), pursuant to which the Company is acquiring all of the
stock of the Holder.  All capitalized terms used and not otherwise defined
herein shall have the meanings assigned to them in the Purchase Agreement.

1.   Payments.
     --------

     1.1.  Subject to the mandatory conversion of this Note into Shares (as
defined and provided for in Section 2 hereof) pursuant to Section 2.1 hereof,
the amount of this Note shall be payable in full on the Maturity Date.

     1.2.  Payment of this Note shall be made to Holder at 29304 Spruce Cyn
Drive, Golden, CO 80403, or such other place or places within the United States
as may be specified by the Holder of this Note in a written notice to the
Company at least 10 business days before the payment date.

     1.3.  Such payment shall be made in lawful money of the United States of
America by mailing the Company's good check in the proper amount to such Holder
on the due date of such payment or otherwise transferring funds for receipt by
such Holder on the due date of such payment.

     1.4.  If payment on this Note becomes due and payable on a Saturday, Sunday
or other day on which commercial banks in New York City are authorized or
required by law to close, the maturity thereof shall be extended to the next
succeeding business day.

     1.5.  In no event shall the amount of interest due or payable hereunder
exceed the maximum rate of interest allowable by applicable law.  It is the
express intent hereof that the Company not pay, and the Holder not receive,
directly or indirectly in any manner whatsoever, interest in excess of that
which may be legally paid by the Company under applicable law.

                                       1
<PAGE>

2.   Conversion Right.
     ----------------

     2.1.  Subject to the provisions of this Section 2, this Note shall
automatically and without any further action by the Company or the Holder
convert into unregistered, fully paid and nonassessable shares ("Shares") of the
Company in the manner and at the Conversion Price set forth below one (1) day
after the first year anniversary of the date of this Note (the date of such
conversion, the "Conversion Date").

     2.2.  For purposes of the conversion calculation only, the price at which
Shares shall be valued (the "Conversion Price") shall be the Closing Price;
provided, however, that the Conversion Price shall be adjusted (as determined in
--------  -------                                                              
good faith by the Board of Directors of the Company) to give appropriate effect
to the occurrence prior to the Conversion Date of any dividend paid by the
Company in cash or other property, Shares, stock split or combination of Shares,
reclassification of Shares or capital reorganization of the Company.  The number
of Shares issuable upon conversion of this Note shall be determined by dividing
the principal amount of the Note (less the amount of any set-off pursuant to
Section 4 hereof) by the Conversion Price, rounding any fractional result down
to the nearest whole share.  No fractional shares shall be issued upon
conversion of this Note.  In lieu of fractional shares, the Company shall pay
cash (based on the Conversion Price) equal to any fraction of a share remaining
(the "Cash Payment").

     2.3.  On the Conversion Date, the Holder shall surrender this Note at the
office of the transfer agent for the Shares (or at the principal office of the
Company if the Company serves as its own transfer agent), together with written
notice that shall state such Holder's name or the names of the nominee(s) in
which such Holder wishes the certificate or certificates for Shares to be
issued.  The certificates for the Shares shall be issued in the name of the
Holder (or its nominees) as of the Conversion Date (subject to the set-off and
recoupment provisions in Section 4 hereof).  Until the Conversion Date (and
then, only if this Note is converted pursuant to the provisions of Section 2.1
hereof), the Holder shall not be entitled to sell, transfer, pledge or encumber
any such Shares, but shall be entitled to vote such shares and to receive any
dividends, merger consideration and stock splits having a record date on or
after the Conversion Date with respect to that number of Shares ultimately
delivered to the Holder with respect to such payment.  The Company shall, on the
Conversion Date (subject to the provisions of Section 4 hereof), cause there to
be delivered to the Holder on such Conversion Date (or to the Holder's
nominee(s) if so instructed in writing) (i) certificates representing the number
of full shares of unregistered, fully paid and nonassessable shares into which
such principal amount may be converted in accordance with the provisions hereof
(subject to reduction pursuant to Section 4 hereof) and (ii) a check in the
amount of the Cash Payment, if any.

3.   Cancellation of Note.
     --------------------

Upon payment in full (and/or set-off (as provided in Section 4 hereof)) of all
outstanding obligations under this Note or the receipt by the Holder of the
appropriate number of Shares upon conversion of the Note into Shares pursuant to
Section 2, the Company's obligations in respect of payment of this Note shall
terminate and the Holder shall surrender this Note to the Company.

4.   Set-off and Recoupment Rights.
     -----------------------------

The Company, by its execution of this Note, and each Holder by its acceptance of
this Note, covenants and agrees that the Company may, in the event a Buyer
Indemnified Party suffers any Buyer Loss required to be paid by the Holder
pursuant to the Purchase Agreement, set-off against its obligations under this
Note and recoup the amounts of any Buyer Losses up to an amount equal to
$338,100 Company will give to the Holder of this Note, written notice of such
election, which includes the amount to be set-off, and the amount of obligations
under this Note shall automatically be reduced by the amount set forth in such
notice as fully as if such amount had been paid to the Holder by the Company;
provided, however, that any disputed set-off amount shall be deducted from this
--------  -------                                                             
Note, and a new Note in such disputed amount shall be deposited in the Escrow
Account; provided, further, that upon any conversion of this Note, a number of
         --------  -------                                                   
shares with an aggregate value (based on the Conversion Price) equal to $169,050
shall be placed in the Escrow Account and held pursuant to terms thereof.

5.   Events of Default.  In the event that:
     -----------------                    

                                       2
<PAGE>

     (a)   the Company defaults for more than ten (10) Business Days in making
           the payment of principal or interest required to be made on this
           Note; or

     (b)   the Company:

           (i)  commences any case, proceeding or other action (x) under any
                existing or future law of any jurisdiction, domestic or foreign,
                relating to bankruptcy, insolvency, reorganization or relief of
                debtors, seeking to have an order for relief entered with
                respect to it, or seeking to adjudicate it a bankrupt or
                insolvent, or seeking reorganization, arrangement, composition
                or other relief with respect to it or its debts or (y) seeking
                appointment of a receiver, trustee, custodian or other similar
                official for it or for all or any substantial part of its
                assets, or shall make a general assignment for the benefit of
                its creditor; or

           (ii) is the debtor named in any other case, proceeding or other
                action of a nature referred to in clause (i) above which (A)
                results in the entry of an order for relief or any such
                adjudication or appointment or (B) remains undismissed,
                undischarged or unbonded for a period of sixty (60) days; or (C)
                takes any action in furtherance of, or indicating its consent
                to, approval of, or acquiescence in, any of the facts set forth
                in clause (i) or (ii) above; or (D) shall generally not, or
                shall be unable to, or shall admit in writing its inability to,
                pay its debts as they become due; or

     (c)   with respect to the Company's Notes issued concurrently herewith, the
           Company defaults in the payment of principal or defaults in the
           payment of interest on such Notes and such default continues
           unremedied for a period of more than ten (10) Business Days;

then, and in any such event (an "Event of Default"), and at any time thereafter,
if such Event of Default shall then be continuing, any Holder of this Note may,
by written notice to the Company, declare this Note due and payable, whereupon
this Note shall be due and payable without presentment, demand, protest or other
notice of any kind, all of which are hereby expressly waived.

6.   Investment Representation.
     -------------------------

Each Holder of this Note hereby acknowledges that this Note has not been and
will not be registered and any Shares to be issued upon conversion of this Note
have not been registered (i) under the Securities Act of 1933, as amended (the
"Act"), on the ground that the issuance of this Note is exempt from registration
under Section 4(2) of the Act as not involving any public offering or (ii) under
any applicable state securities law on the ground that the issuance of this Note
does not involve any public offering; and that the Company's reliance on the
Section 4(2) exemption of the Act and on applicable state securities laws is
predicated in part on the representations hereby made to the Company by the
Holder that it is acquiring the Note for investment for its own account, with no
intention of dividing its participation with others  or otherwise distributing
the same, subject, nevertheless, to any requirements of law that the disposition
of its property shall at all times be within its control.

7.   Miscellaneous.
     -------------

     7.1.  Upon receipt of evidence reasonably satisfactory to the Company of
the loss, theft, destruction or mutilation of this Note and of a letter of
indemnity reasonably satisfactory to the Company, and upon reimbursement to the
Company of all reasonable expenses incident thereto, and upon surrender or
cancellation of the Note, if mutilated, the Company will make and deliver a new
Note of like tenor in lieu of such lost, stolen, destroyed or mutilated Note.

     7.2.  In the event that one of the Events of Default specified in Section 5
hereof has occurred and is continuing, the Holder of this Note shall be
reimbursed by the Company for the payment of its reasonable attorneys' fees
actually paid relating to the enforcement of any of the provisions of this Note.

                                       3
<PAGE>

     7.3.  This Note and the rights and obligations of the Company and any
Holder hereunder shall be construed in accordance with and be governed by the
laws of the State of New York and shall be subject to the arbitration provisions
set forth in the Purchase Agreement as if expressly included herein.

     7.4   Time is of the essence of this Note.  If any provisions of this Note
or the application thereof to any person or circumstance shall be invalid or
unenforceable to any extent, the remainder of this Note and the application of
such provisions to other persons or circumstances shall not be affected thereby
and shall be enforced to the greatest extent permitted by law.

                                       4
<PAGE>

     IN WITNESS WHEREOF, the Company has executed this Note as of the day and
year first above written.

                        EARTHWEB INC.

                            By:    /s/ Jack Hidary
                                   --------------------------------------------
                                   Name:  Jack Hidary
                                   Title: President and Chief Executive Officer
[SEAL]

Attest:


/s/ Murray Hidary
------------------

                                       5

Source: OneCLE Business Contracts.