Document:

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                             PAPEREXCHANGE.COM, LLC

                                 PROMISSORY NOTE

$                                                               October 15, 1999
 -------------                                             Boston, Massachusetts

      For value received, PAPEREXCHANGE.COM, LLC, a Delaware limited liability
company (the "Company"), promises to pay to the order of _________ (including
any permitted transferee hereunder, the "Holder"), the principal sum of ______
Dollars ($_______) on October 15, 2004. Interest shall accrue from the date of
this Note on the unpaid principal amount at an annual rate equal to the
announced base rate of BankBoston, N.A. (or any successor thereto) (the "Base
Rate") plus four percent (4%). Such interest rate shall change when and as the
Base Rate changes. This Note is being issued in connection and simultaneously
with a certain warrant to purchase Membership Interests of the Company issued to
the Holder as of the date hereof. This Note is one of nine promissory notes
being issued on the date hereof in the aggregate amount of $10,000,000 (the
"Notes"). This Note is subject to the following terms and conditions.

      1.    Advances, Interest and Maturity.

            (a) On the date hereof, Holder is lending $_________ to the Company.

            (b) Interest shall be payable quarterly in arrears on each of March
31, June 30, September 30 and December 31 of each year commencing on December
31, 1999.

            (c) Unpaid principal and interest under this Note shall be due and
payable upon the earlier of (a) October 15, 2004, and (b) the date of an
Acceleration pursuant to Section 3 hereof.

      2. Payment. All payments shall be made in lawful money of the United
States of America at such place in the United States as the Holder hereof may
from time to time designate in writing to the Company. The Company shall have
the right to prepay, in whole or in part, the unpaid principal amount of this
Note on ten (10) business days' prior written notice to the Holder. Any
prepayment of the principal amount of this Note shall be made without premium or
prepayment penalty, provided that the Company shall pay all accrued interest to
the date of prepayment on the principal amount prepaid.

      3. Acceleration Events. Each of the following events or circumstances
shall constitute an "Acceleration Event":

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                                       2

            (a) the Company shall fail to pay any amount of principal or
interest within five (5) days of the date on which such amount is due and
payable hereunder, or

            (b) any sale or transfer, in a single transaction or a series of
related transactions, of all or substantially all of the Company's assets, or
any merger, consolidation or reorganization resulting in a change of control of
the Company, or the dissolution of the Company, or the sale, in a single
transaction or a series of related transactions, of a majority of the Company's
Membership Interests (whether newly issued, previously issued, or any
combination thereof);

            (c) the Company shall fail to perform any of its other obligations
or agreements set forth herein, and such failure shall continue for a period of
ten (10) days after notice of such failure is given by the Holder to the
Company;

            (d) the Company shall make an assignment for the benefit of
creditors, or admit in writing its inability to pay or generally fail to pay its
debts as they mature or become due, or shall petition or apply for the
appointment of a trustee or other custodian, liquidator or receiver of the
Company or of any substantial part of its assets or shall commence any case or
other proceeding relating to its assets under any bankruptcy, reorganization,
arrangement, insolvency, readjustment of debt, dissolution or liquidation or
similar law of any jurisdiction, or shall take any action to authorize or in
furtherance of any of the foregoing; or any such petition or application shall
be filed or any such case or other proceeding shall be commenced against the
Company, and the same shall not have been dismissed within 60 days of the filing
or commencement thereof or the Company shall indicate its approval thereof,
consent thereto or acquiescence therein; or a decree or order shall be entered
appointing any such trustee, custodian, liquidator or receiver or adjudicating
the Company bankrupt or insolvent, or approving a petition in any such case or
other proceeding, or a decree or order for relief shall be entered in respect of
the Company in an involuntary case under any such bankruptcy or insolvency laws;
and

            (e) the Company shall, in one transaction or a series of related
transactions, issue any debt and/or equity or incur any debt for money borrowed,
including, but not limited to, the issuance of any notes, shares, interests,
Membership Interests, participations, rights or other equivalents (howsoever
designated) of the Company, of which the gross proceeds to the Company with
respect to such issuance or loan exceed $30,000,000.00.

      If an Acceleration Event pursuant to Sections 3(a), 3(b), 3(c) or 3(e)
hereof shall occur, and only if the Majority Holders declare the entire unpaid
principal of the Majority Holders' respective Notes and all interest payable on
or in respect of the Majority Holders' respective Notes and the obligations
evidenced thereby due and payable, the Holder at its option at any time
thereafter during the continuance of

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                                       3

such Acceleration Event may declare the entire and unpaid principal of this Note
and all interest payable on or in respect of this Note and the obligations
evidenced hereby due and payable, and the same shall thereupon forthwith become
and be due and payable to the Holder (an "Acceleration") without presentment,
demand, protest, notice of protest or any other formalities of any kind, all of
which are hereby expressly and irrevocably waived by the Company.

      Notwithstanding anything contained herein, if the Company shall fail to
make three (3) regularly-scheduled consecutive interest payments pursuant to
Section 3(a) hereof, and if the holders of at least twenty-five percent (25%) of
the aggregate principal then outstanding under the Notes ("Twenty-Five Percent
Holders") declare the entire unpaid principal of the Notes and all interest
payable on or in respect of the Notes and the obligations evidenced thereby due
and payable, the Holder at its option at any time thereafter during the
continuance of such Acceleration Event may declare the entire and unpaid
principal of this Note and all interest payable on or in respect of this Note
and the obligations evidenced hereby due and payable, and the same shall
thereupon forthwith become and be due and payable to the Holder without
presentment, demand, protest, notice of protest or any other formalities of any
kind, all of which are hereby expressly and irrevocably waived by the Company.

      In the event of an Acceleration Event under Section 3(d) hereof, the
entire unpaid principal of this Note and all interest payable on or in respect
of this Note and the obligations evidenced hereby due and payable shall become
and be immediately due and payable, and an Acceleration shall be deemed for all
purposes hereof to have occurred, automatically and without any requirement of
notice from the Holder.

      4. Definitions. As used herein, the following terms, unless the context
otherwise requires, have the following respective meanings:

      Acceleration shall have the meaning set forth in the third to the last
paragraph of Section 3 hereof.

      Acceleration Event shall have the meaning set forth in the first paragraph
of Section 3 hereof.

      Base Rate shall have the meaning set forth in the first paragraph of this
Note.

      Company shall have the meaning set forth in the first paragraph of this
Note.

      Final Maturity Date  shall mean October 15, 2004.

      Holder shall have the meaning set forth in the first paragraph of this
Note.

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                                       4

      Majority Holders shall mean the holders of a majority of the aggregate
principal then outstanding under the Notes.

      Membership Interests shall mean the Membership Interests of the Company
and such other classes of units of the Company as may hereafter succeed to any
of the rights of the Membership Interests.

      Notes shall have the meaning set forth in the first paragraph of this
Note.

      Operating Agreement shall mean the Company's Amended and Restated
Operating Agreement, dated as of June 1, 1999.

      Twenty-Five Percent Holders shall have the meaning set forth in the
penultimate paragraph of Section 3 hereof.

      5. Capitalization Table. The Company represents that the capitalization
table attached hereto as Exhibit A is true and correct as of the date hereof.

      6. Transfer; Successors and Assigns. The terms and conditions of this Note
shall inure to the benefit of and be binding upon the respective successors and
assigns of the parties. Notwithstanding the foregoing, the Holder may not
assign, pledge, or otherwise transfer this Note without the prior written
consent of the Company and the Majority Holders. Notwithstanding anything
contained in the preceding sentence, and except with respect to transfers to
Affiliates (as such term is defined in the Operating Agreement) this Note is
transferable only to the extent, and only as to the pro rata portion, that the
warrant issued to the Holder simultaneously herewith is transferred.

      7. Governing Law. This Note and all acts and transactions pursuant hereto
and the rights and obligations of the parties hereto shall be governed,
construed and interpreted in accordance with the laws of the Commonwealth of
Massachusetts, without giving effect to its principles of conflicts of law.

      8. Notices. Any notice required or permitted by this Note shall be in
writing and shall be deemed sufficient upon delivery, when delivered personally
or by a nationally-recognized delivery service (such as Federal Express or UPS),
or ninety-six (96) hours after being deposited in the U.S. mail, as certified or
registered mail, with postage prepaid, addressed to the party to be notified.
Notices to the Holder shall be sent to the address of the Holder on the books of
the Company or to such other address as may be designated by the Holder by
notice given to the Company in accordance with this paragraph, and notices to
the Company shall be sent to its address at 545 Boylston Street, 8th floor,
Boston, Massachusetts 02116, or to such other address as may be designated by
the Company by notice given to the Holder in accordance with this Section 8.

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                                       5

      9. Amendments and Waivers. Any term of this Note may be amended only with
the written consent of the Company and the Majority Holders; provided, however,
that an amendment which (i) reduces the aggregate amount of principal due under
this Note, (ii) reduces the rate of interest due under this Note, or (iii)
extends the Final Maturity Date shall require the written consent of the Holder
hereof. Any amendment or waiver effected in accordance with this Section 9 shall
be binding upon the Company, the Holder and each transferee of the Note. The
Company expressly waives presentment, demand, notice, protest and all other
demands and notices in connection with the delivery, acceptance, performance,
default or enforcement of this Note.

      10. Members and Directors Not Liable. In no event shall any Member or
Director (each as defined in the Operating Agreement) of the Company be liable
for any amounts due or payable pursuant to this Note.

      11. Waiver of Jury Trial. The Company and the Holder hereby waive their
right to a jury trial with respect to any action or claim arising out of any
dispute in connection with this Note, any rights or obligations hereunder or the
performance of any of such rights or obligations.

      12. Action to Collect on Note. If any action is instituted to collect on
this Note, the Company promises to pay all costs and expenses, including
reasonable attorney's fees, incurred by the Holder in connection with such
action and the collection of this Note.

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      This Note shall be deemed to take effect as a sealed instrument under the
laws of The Commonwealth of Massachusetts.

                                    COMPANY:

                                    PAPEREXCHANGE.COM, LLC

                                    By:
                                       ----------------------------------

                                           Its:<PAGE>
                                                             Exhibit 10.23

                        AMENDMENT TO EMPLOYMENT AGREEMENT

                                  HILTON PLEIN

      This Amendment to Employment Agreement (the "Amendment") is made to be
effective as of May 12, 1999 (the "Effective Date") by and between
PAPEREXCHANGE.COM, LLC, a Delaware limited liability company (the "Company"),
and Hilton Plein ("Employee").

                                    RECITALS

1.    Employee and the Company previously entered into that certain Employment
      Agreement effective as of April 9, 1998 (the "Agreement").

2.    Since entering into the Agreement, the circumstances pertaining to
      Employee's provision of services to the Company has changed such that the
      Company and Employee believe it to be in the best interest of both parties
      to amend the Agreement.

                              OPERATIVE PROVISIONS

      In consideration of the above recitals, which are incorporated into and
are material part of the operative provisions of this Amendment, and of the
promises, covenants and conditions stated herein, Company and Employee agree to
amend the Agreement as follows:

                                       1.
<PAGE>

      A. Section 1 and subsection 1.1 of the Agreement shall be deleted and
shall hereafter read as follows:

      "1. TITLE; POSITION AND RESPONSIBILITIES

      1.1 During the period of Employee's employment hereunder, Employee's title
shall be one mutually acceptable to Employee and the Company's Chief Technology
Officer. Employee shall render administrative and management services to the
Company as delegated by the Company's Management board or the Company's Chief
Technology Officer. Employee shall report directly to the Company's Chief
Technology Officer."

      B. A new subsection 1.2 shall be added to the Agreement, and shall read as
follows:

      "1.2 Nothing contained herein shall be construed to require Employee to
relocate."

      C. Subsection 2.1 of the Agreement shall be deleted and hereafter shall
read as follows:

      "2.1 The period of Employee's employment under this Agreement shall be
deemed to have commenced on May 12, 1999 and shall continue for a period of five
(5) full years thereafter. At the end of the five (5) year period, this
Agreement shall be automatically renewed for consecutive one-year renewal terms
unless the Company provides written notice of non-renewal at least ninety (90)
days prior to the end of the initial five (5) year period; or, if renewed for
one or more one-year renewal periods, written notice of non-renewal must be
given by Employee or the Company not less than thirty (30) days prior to the end
of the then current renewal period."

      D. The title to Section 3 of the Agreement shall be amended to read as
follows:

                                       2.
<PAGE>

      "3. COMPENSATION, REIMBURSEMENT, BENEFITS; MISCELLANEOUS"

      E. Subsection 3.1 of the Agreement shall be deleted and hereafter shall
read as follows:

      "3.1 The compensation specified under this Agreement shall constitute the
salary and benefits paid for Employee's performance of the duties described in
Article 1. The Company shall pay Employee as compensation a salary of not less
than $120,000 per year ("Base Salary"). The Base Salary shall be payable in
accordance with Company's payroll practices. During the period of this
Agreement, Employee's Base Salary shall be reviewed for the determination of
whether any merit increases are warranted. No downward adjustment shall be made
in the Base Salary without Employee's written approval, which approval may be
withheld by Employee in his sole and absolute discretion. In addition to the
annual merit review, at the end of every twelve month period from the date
hereof, Employee's Base Salary shall be adjusted based on the inflation rate for
information technology professionals, as determined by a reasonable third party
source such as Information Week. Following any adjustment of the Base Salary
pursuant to this Section 3.1, the adjusted Base Salary thereafter shall become
the "Base Salary" for purposes of this Agreement."

      F (I). Subsection 3.2 of the Agreement shall be deleted and thereafter
shall read as follows:

      "3.2 Employee shall be entitled to participate in any staff-wide bonus
program, if any, offered by the Company."

      F (II). The first sentence of Section 3.3 is modified to read as follows
"The Company shall also provide Employee, at no cost to Employee, with a health
insurance policy pursuant to

                                       3.
<PAGE>

the Company's group health insurance policy or policies as in effect from time
to time and made available to senior executives of the Company.

      G. Subsection 3.4 of the Agreement shall be deleted and thereafter shall
read as follows:

      "3.4 Employee shall be entitled to a one-time cash bonus in the amount of
$5,000, which shall be payable on the last business day of December 1999."

      H. Subsection 3.8 of the Agreement shall be deleted and thereafter shall
read as follows:

      "3.8 The Company shall grant Employee three (3) weeks of fully compensated
vacation per annum under this Agreement."

      I. A new subsection 3.9 shall be added to the Agreement and shall read as
follows:

      "3.9 If a new position is created within the Company, the Company agrees
to give Employee a good-faith assessment review for that position, if Employee
so requests an opportunity to fill that position. Thereafter, if Employee
assumes such new position and the Company, in good-faith, determines that such
new position warrants a higher salary, the Company will immediately adjust
Employee's Base Salary accordingly."

      J. A new Subsection 3.10 shall be added to the Agreement and shall read as
follows:

      "3.10 The Company will appoint Employee as a member of its Advisory Board
once the Company establishes the Advisory Board; provided, however, that
Employee understands and agrees that he will not be entitled to any compensation
for service on the Advisory Board."

                                       4.
<PAGE>

      K. A new Subsection 3.11 shall be added to the Agreement and shall read as
follows:

      "3.11 The Company agrees that in any and all of its communications to
third parties, it will refer to Employee as a founder of the Company."

      L. All other provisions of the Agreement not deleted or amended hereby
shall remain in full force and effect through the term of the Agreement, as such
term has been modified by this Amendment.

            Company and Employee have executed this Amendment to be effective on
and as of the Effective Date given hereinabove.

            "EMPLOYEE"

            By: /s/ Hilton Plein
                --------------------------------------
                Hilton Plein

            "COMPANY"

            PAPEREXCHANGE.COM, LLC

            By: /s/ Jason Weiss
                --------------------------------------

                    Name:
                         -----------------------------

                    Title:
                          ----------------------------

                                       5.
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I, Hilton Plein do hereby consent to have the closing of the Purchase Agreement
moved from May 12, 1999 to May 14, 1999 if the documents are signed today May
12, 1999.

/s/ Hilton Plein
---------------------------
Hilton Plein

Date: May 12, 1999
      ---------------------
<PAGE>

      IN WITNESS WHEREOF, the parties of this Agreement have duly executed this
Agreement or have caused this Agreement to be duly executed on the day and year
first above written.

      HILTON PLEIN

      /s/ Hilton Plein
      ----------------------------------
      Hilton Plein

      KRAFT GROUP, LLC

      By /s/ Robert Kraft
         -------------------------------

         Name:
              --------------------------

         Title:
               -------------------------

      PAPEREXCHANGE.COM, LLC

      By /s/ Jason Weiss
         -------------------------------

         Name: Jason Weiss
              --------------------------

         Title: CEO
               -------------------------

     TERRAPIN PARTNERS, LLC

      By /s/ Jason Weiss
         -------------------------------

         Name: Jason Weiss
              --------------------------

         Title: Managing Partner
               -------------------------

                                       6.
<PAGE>

                        RESIGNATION FROM MANAGEMENT BOARD

I Hilton Plein hereby resign my seat on the Management Board of
PaperExchange.com, LLC.

Executed at Chicago IL on May 12th, 1999

/s/ Hilton Plein
----------------------------------
HILTON PLEIN

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