<PAGE>   1
         As filed with the Securities and Exchange Commission on August 27, 2001
                                        Registration No. 333-
                                                             -------------------


                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM S-8
                             REGISTRATION STATEMENT

                                      UNDER
                           THE SECURITIES ACT OF 1933

                               DIGITALTHINK, INC.
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

<TABLE>
<S>                                            <C>                                        <C>
           DELAWARE                                      7372                                  94-3244366
(STATE OR OTHER JURISDICTION OF               (PRIMARY STANDARD INDUSTRIAL                   (I.R.S. EMPLOYER
 INCORPORATION OR ORGANIZATION)               CLASSIFICATION CODE NUMBER)                 IDENTIFICATION NUMBER)
                                                  1098 HARRISON STREET
                                                 SAN FRANCISCO, CA 94103
                                                      (415) 625-4000
</TABLE>

          (ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING
            AREA CODE, OF REGISTRANT'S PRINCIPAL EXECUTIVE OFFICES)

                                 1996 STOCK PLAN
                        1999 EMPLOYEE STOCK PURCHASE PLAN
                            (FULL TITLE OF THE PLANS)

                                 JON C. MADONNA
                             CHIEF EXECUTIVE OFFICER
                               DIGITALTHINK, INC.
                              1098 HARRISON STREET
                             SAN FRANCISCO, CA 94103
                                 (415) 625-4000

       (NAME, ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING
                        AREA CODE, OF AGENT FOR SERVICE)

                                   Copies to:
                          CHRISTOPHER D. MITCHELL, ESQ.
                        WILSON SONSINI GOODRICH & ROSATI
                            PROFESSIONAL CORPORATION
                               650 PAGE MILL ROAD
                               PALO ALTO, CA 94304

     APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC: AS SOON AS
PRACTICABLE AFTER THE EFFECTIVE DATE OF THIS REGISTRATION STATEMENT.

     IF ANY OF THE SECURITIES BEING REGISTERED ON THIS FORM ARE TO BE OFFERED
ON A DELAYED OR CONTINUOUS BASIS PURSUANT TO RULE 415 UNDER THE SECURITIES ACT
OF 1933, CHECK THE FOLLOWING BOX. [X]
<PAGE>   2

                         CALCULATION OF REGISTRATION FEE
<TABLE>
<CAPTION>
===============================================================================================================================
                                                                      PROPOSED
                                                                       MAXIMUM                PROPOSED
                                                   AMOUNT             OFFERING                 MAXIMUM
  TITLE OF EACH CLASS OF SECURITIES TO             TO BE                PRICE                AGGREGATE           AMOUNT OF
             BE REGISTERED                       REGISTERED           PER SHARE           OFFERING PRICE      REGISTRATION FEE
-------------------------------------------------------------------------------------------------------------------------------
<S>                                              <C>                  <C>                 <C>                  <C>
1996 Stock Plan
Common Stock, $0.001 par value
(currently outstanding options)(2)                 351,905            $ 7.930             $ 2,790,606.65           $  697.65
-------------------------------------------------------------------------------------------------------------------------------
1996 Stock Plan
Common Stock, $0.001 par value
(options available for future grant)(3)          1,400,273            $12.885             $18,042,517.61           $4,510.63
-------------------------------------------------------------------------------------------------------------------------------
Total 1996 Stock Plan shares registered (1)      1,752,178
-------------------------------------------------------------------------------------------------------------------------------
Common Stock, $0.001 par value, to be
issued under the 1999 Employee Stock
Purchase Plan (4)(5)                               350,435             $10.95             $ 3,838,051.73            $  959.51
-------------------------------------------------------------------------------------------------------------------------------
        TOTAL REGISTRATION FEES:                                                                                    $6,167.79
===============================================================================================================================
</TABLE>

     (1)  Represents shares of Common Stock which have become available for
          issuance under the Registrant's 1996 Stock Plan as a result of the
          automatic "evergreen provision" effective upon the commencement of the
          Registrant's fiscal year, April 1, 2001. This represents 5% of the
          Registrant's Common Stock on March 31, 2001.

     (2)  The computation is based upon the weighted average exercise price per
          share of $7.930 as to 351,905 outstanding but unexercised options to
          purchase Common Stock under the 1996 Stock Plan.

     (3)  The Proposed Maximum Offering Price Per Share has been estimated in
          accordance with Rule 457(h) under the Securities Act of 1933 as to the
          remaining 1,400,273 shares of Common Stock authorized for issuance
          pursuant to the 1996 Stock Plan, solely for the purpose of calculating
          the registration fee. No options have been granted with respect to
          such shares. The computation is based upon the average of the high and
          low price of the Common Stock as reported on the Nasdaq National
          Market on August 20, 2001 because the price at which the options to be
          granted in the future may be exercised is not currently determinable.

     (4)  Represents shares of Common Stock which have become available for
          issuance under the Registrant's 1999 Employee Stock Purchase Plan as a
          result of an automatic "evergreen provision" effective upon the
          commencement of the Registrant's fiscal year, April 1, 2001. This
          represents 1% of the Registrant's Common Stock on March 31, 2001.

     (5)  The Proposed Maximum Offering Price Per Share has been estimated in
          accordance with Rule 457(h) under the Securities Act of 1933 solely
          for the purpose of calculating the registration fee. The computation
          is based upon 85% (see explanation in following sentence) of the
          average of the high and low price of the Common Stock as reported on
          the Nasdaq National Market on August 20, 2001 because the price at
          which the options to be granted in the future may be exercised is not
          currently determinable. Pursuant to the Employee Stock Purchase Plan,
          which plan is incorporated by reference herein, the Purchase Price of
          a share of Common Stock shall mean an amount equal to 85% of the Fair
          Market Value of a share of Common Stock on the Enrollment Date or the
          Exercise Date, whichever is lower.


<PAGE>   3


             STATEMENT UNDER GENERAL INSTRUCTION E - REGISTRATION OF
                              ADDITIONAL SECURITIES

     This Registration Statement registers additional shares of the Registrant's
Common Stock to be issued pursuant to the 1996 Stock Plan and the 1999 Employee
Stock Purchase Plan. Accordingly, the contents of the previous Registration
Statements on Form S-8 (File No. 333-43284 and File No. 333-56770) (the
"Previous Form S-8") filed by the Registrant with the Securities and Exchange
Commission ("SEC"), including periodic reports that the Registrant filed after
the Previous Form S-8 to maintain current information about the Registrant, are
incorporated by reference into this Registration Statement pursuant to General
Instruction E of Form S-8. The reports the Registrant has most recently filed
with the SEC are listed below:

     (a)  The Registrant's Annual Report on Form 10-K for the fiscal year ended
          March 31, 2001, as filed pursuant to Section 13(a) of the Securities
          Exchange Act of 1934, as amended (the "Exchange Act"), on June 11,
          2001.

     (b)  The Registrant's Quarterly Report on Form 10-Q for the quarterly
          period ended March 31, 2001, as filed pursuant to Section 13 (a) of
          the Exchange Act on August 8, 2001.

     (c)  Proxy Statement filed as of June 8, 2001 in connection with the Annual
          Meeting of Stockholders held on July 27, 2001.


                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 8. EXHIBITS.

     The  Exhibits listed on the accompanying Index to Exhibits are filed as
part hereof, or incorporated by reference into, this Registration Statement.
(See Exhibit Index below).
<PAGE>   4

                                   SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, as amended, the
Registrant certifies that it has reasonable grounds to believe that it meets all
of the requirements for filing on Form S-8 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized in the City of San Francisco, State of California on August 24, 2001.

                                 DIGITALTHINK, INC.

                                 By: /s/ JON C. MADONNA
                                    --------------------------------------------
                                    Jon C. Madonna
                                    Chief Executive Officer and President

                                POWER OF ATTORNEY

     KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints Jon C. Madonna and Michael W. Pope,
jointly and severally, his attorneys-in-fact, each with the power of
substitution, for him in any and all capacities, to sign any amendments to this
Registration Statement on Form S-8, and to file the same, with exhibits thereto
and other documents in connection therewith, with the Securities and Exchange
Commission, hereby ratifying and confirming all that each of said
attorneys-in-fact, or his substitute or substitutes, may do or cause to be done
by virtue hereof.

     Pursuant to the requirements of the Securities Act of 1933, as amended,
this Registration Statement has been signed by the following persons in the
capacities and on the date indicated.
<TABLE>
<CAPTION>
                      SIGNATURE                                       TITLE                        DATE
------------------------------------------------------    ----------------------------     -----------------------
<S>                                                       <C>                                   <C>
 /s/ JON C. MADONNA                                       Chief Executive Officer and           August 24, 2001
-------------------------------------------------------   President
     Jon C. Madonna

/s/ MICHAEL W. POPE                                       Vice President, Chief Financial       August 24, 2001
-------------------------------------------------------   Officer
    Michael W. Pope

/s/ PETER J. GOETTNER                                     Chairman of the Board                 August 24, 2001
-------------------------------------------------------
    Peter J. Goettner

/s/ E. FOLLETT CARTER                                     Director                              August 24, 2001
------------------------------------------------------
    E. Follett Carter

/s/ STEVEN L. ESKENAZI              .                     Director                              August 24, 2001
-------------------------------------------------------
    Steven L. Eskenazi

/s/ SAMUEL D. KINGSLAND                                   Director                              August 24, 2001
-------------------------------------------------------
    Samuel D. Kingsland

/s/ WILLIAM H. LANE III              .                    Director                              August 24, 2001
-------------------------------------------------------
    William H. Lane III

/s/ RODERICK C. MCGEARY                                   Director                              August 24, 2001
-------------------------------------------------------
    Roderick C. McGeary
</TABLE>
<PAGE>   5

                                INDEX TO EXHIBITS

<TABLE>
<S>                   <C>
 EXHIBIT NUMBER                      EXHIBIT DOCUMENT
-------------------   ---------------------------------------------
      5.1             Opinion of Counsel

     23.1             Independent Auditor's Consent

     23.2             Consent of Counsel (contained in Exhibit 5.1 hereto)

     24.1             Power of Attorney (see signature page)
</TABLE>
[{"type": "S-8", "sequence": "1", "filename": "f75380ors-8.txt", "description": "FORM S-8", "secsgml_size_bytes": 13453}]
{"company-data": {"conformed-name": "DIGITALTHINK INC", "cik": "0001100514", "assigned-sic": "7389", "irs-number": "943244366", "state-of-incorporation": "DE", "fiscal-year-end": "0331"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-68384", "film-number": "1723821"}, "business-address": {"street1": "1098 HARRISON ST", "city": "SAN FRANCISCO", "state": "CA", "zip": "94103", "phone": "4156254000"}}
1
         As filed with the Securities and Exchange Commission on August 27, 2001
                                        Registration No. 333-
                                                             -------------------

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM S-8
                             REGISTRATION STATEMENT

                                      UNDER
                           THE SECURITIES ACT OF 1933

                               DIGITALTHINK, INC.
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)
DELAWARE                                      7372                                  94-3244366
(STATE OR OTHER JURISDICTION OF               (PRIMARY STANDARD INDUSTRIAL                   (I.R.S. EMPLOYER
 INCORPORATION OR ORGANIZATION)               CLASSIFICATION CODE NUMBER)                 IDENTIFICATION NUMBER)
                                                  1098 HARRISON STREET
                                                 SAN FRANCISCO, CA 94103
                                                      (415) 625-4000
(ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING
            AREA CODE, OF REGISTRANT'S PRINCIPAL EXECUTIVE OFFICES)

                                 1996 STOCK PLAN
                        1999 EMPLOYEE STOCK PURCHASE PLAN
                            (FULL TITLE OF THE PLANS)

                                 JON C. MADONNA
                             CHIEF EXECUTIVE OFFICER
                               DIGITALTHINK, INC.
                              1098 HARRISON STREET
                             SAN FRANCISCO, CA 94103
                                 (415) 625-4000

       (NAME, ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING
                        AREA CODE, OF AGENT FOR SERVICE)

                                   Copies to:
                          CHRISTOPHER D. MITCHELL, ESQ.
                        WILSON SONSINI GOODRICH & ROSATI
                            PROFESSIONAL CORPORATION
                               650 PAGE MILL ROAD
                               PALO ALTO, CA 94304

     APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC: AS SOON AS
PRACTICABLE AFTER THE EFFECTIVE DATE OF THIS REGISTRATION STATEMENT.

     IF ANY OF THE SECURITIES BEING REGISTERED ON THIS FORM ARE TO BE OFFERED
ON A DELAYED OR CONTINUOUS BASIS PURSUANT TO RULE 415 UNDER THE SECURITIES ACT
OF 1933, CHECK THE FOLLOWING BOX. [X]
2

                         CALCULATION OF REGISTRATION FEE
===============================================================================================================================
                                                                      PROPOSED
                                                                       MAXIMUM                PROPOSED
                                                   AMOUNT             OFFERING                 MAXIMUM
  TITLE OF EACH CLASS OF SECURITIES TO             TO BE                PRICE                AGGREGATE           AMOUNT OF
             BE REGISTERED                       REGISTERED           PER SHARE           OFFERING PRICE      REGISTRATION FEE
-------------------------------------------------------------------------------------------------------------------------------
1996 Stock Plan
Common Stock, $0.001 par value
(currently outstanding options)(2)                 351,905            $ 7.930             $ 2,790,606.65           $  697.65
-------------------------------------------------------------------------------------------------------------------------------
1996 Stock Plan
Common Stock, $0.001 par value
(options available for future grant)(3)          1,400,273            $12.885             $18,042,517.61           $4,510.63
-------------------------------------------------------------------------------------------------------------------------------
Total 1996 Stock Plan shares registered (1)      1,752,178
-------------------------------------------------------------------------------------------------------------------------------
Common Stock, $0.001 par value, to be
issued under the 1999 Employee Stock
Purchase Plan (4)(5)                               350,435             $10.95             $ 3,838,051.73            $  959.51
-------------------------------------------------------------------------------------------------------------------------------
        TOTAL REGISTRATION FEES:                                                                                    $6,167.79
===============================================================================================================================
(1)  Represents shares of Common Stock which have become available for
          issuance under the Registrant's 1996 Stock Plan as a result of the
          automatic "evergreen provision" effective upon the commencement of the
          Registrant's fiscal year, April 1, 2001. This represents 5% of the
          Registrant's Common Stock on March 31, 2001.

     (2)  The computation is based upon the weighted average exercise price per
          share of $7.930 as to 351,905 outstanding but unexercised options to
          purchase Common Stock under the 1996 Stock Plan.

     (3)  The Proposed Maximum Offering Price Per Share has been estimated in
          accordance with Rule 457(h) under the Securities Act of 1933 as to the
          remaining 1,400,273 shares of Common Stock authorized for issuance
          pursuant to the 1996 Stock Plan, solely for the purpose of calculating
          the registration fee. No options have been granted with respect to
          such shares. The computation is based upon the average of the high and
          low price of the Common Stock as reported on the Nasdaq National
          Market on August 20, 2001 because the price at which the options to be
          granted in the future may be exercised is not currently determinable.

     (4)  Represents shares of Common Stock which have become available for
          issuance under the Registrant's 1999 Employee Stock Purchase Plan as a
          result of an automatic "evergreen provision" effective upon the
          commencement of the Registrant's fiscal year, April 1, 2001. This
          represents 1% of the Registrant's Common Stock on March 31, 2001.

     (5)  The Proposed Maximum Offering Price Per Share has been estimated in
          accordance with Rule 457(h) under the Securities Act of 1933 solely
          for the purpose of calculating the registration fee. The computation
          is based upon 85% (see explanation in following sentence) of the
          average of the high and low price of the Common Stock as reported on
          the Nasdaq National Market on August 20, 2001 because the price at
          which the options to be granted in the future may be exercised is not
          currently determinable. Pursuant to the Employee Stock Purchase Plan,
          which plan is incorporated by reference herein, the Purchase Price of
          a share of Common Stock shall mean an amount equal to 85% of the Fair
          Market Value of a share of Common Stock on the Enrollment Date or the
          Exercise Date, whichever is lower.
3

             STATEMENT UNDER GENERAL INSTRUCTION E - REGISTRATION OF
                              ADDITIONAL SECURITIES

     This Registration Statement registers additional shares of the Registrant's
Common Stock to be issued pursuant to the 1996 Stock Plan and the 1999 Employee
Stock Purchase Plan. Accordingly, the contents of the previous Registration
Statements on Form S-8 (File No. 333-43284 and File No. 333-56770) (the
"Previous Form S-8") filed by the Registrant with the Securities and Exchange
Commission ("SEC"), including periodic reports that the Registrant filed after
the Previous Form S-8 to maintain current information about the Registrant, are
incorporated by reference into this Registration Statement pursuant to General
Instruction E of Form S-8. The reports the Registrant has most recently filed
with the SEC are listed below:

     (a)  The Registrant's Annual Report on Form 10-K for the fiscal year ended
          March 31, 2001, as filed pursuant to Section 13(a) of the Securities
          Exchange Act of 1934, as amended (the "Exchange Act"), on June 11,
          2001.

     (b)  The Registrant's Quarterly Report on Form 10-Q for the quarterly
          period ended March 31, 2001, as filed pursuant to Section 13 (a) of
          the Exchange Act on August 8, 2001.

     (c)  Proxy Statement filed as of June 8, 2001 in connection with the Annual
          Meeting of Stockholders held on July 27, 2001.

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 8. EXHIBITS.

     The  Exhibits listed on the accompanying Index to Exhibits are filed as
part hereof, or incorporated by reference into, this Registration Statement.
(See Exhibit Index below).
4

                                   SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, as amended, the
Registrant certifies that it has reasonable grounds to believe that it meets all
of the requirements for filing on Form S-8 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized in the City of San Francisco, State of California on August 24, 2001.

                                 DIGITALTHINK, INC.

                                 By: /s/ JON C. MADONNA
                                    --------------------------------------------
                                    Jon C. Madonna
                                    Chief Executive Officer and President

                                POWER OF ATTORNEY

     KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints Jon C. Madonna and Michael W. Pope,
jointly and severally, his attorneys-in-fact, each with the power of
substitution, for him in any and all capacities, to sign any amendments to this
Registration Statement on Form S-8, and to file the same, with exhibits thereto
and other documents in connection therewith, with the Securities and Exchange
Commission, hereby ratifying and confirming all that each of said
attorneys-in-fact, or his substitute or substitutes, may do or cause to be done
by virtue hereof.

     Pursuant to the requirements of the Securities Act of 1933, as amended,
this Registration Statement has been signed by the following persons in the
capacities and on the date indicated.
SIGNATURE                                       TITLE                        DATE
------------------------------------------------------    ----------------------------     -----------------------
/s/ JON C. MADONNA                                       Chief Executive Officer and           August 24, 2001
-------------------------------------------------------   President
     Jon C. Madonna

/s/ MICHAEL W. POPE                                       Vice President, Chief Financial       August 24, 2001
-------------------------------------------------------   Officer
    Michael W. Pope

/s/ PETER J. GOETTNER                                     Chairman of the Board                 August 24, 2001
-------------------------------------------------------
    Peter J. Goettner

/s/ E. FOLLETT CARTER                                     Director                              August 24, 2001
------------------------------------------------------
    E. Follett Carter

/s/ STEVEN L. ESKENAZI              .                     Director                              August 24, 2001
-------------------------------------------------------
    Steven L. Eskenazi

/s/ SAMUEL D. KINGSLAND                                   Director                              August 24, 2001
-------------------------------------------------------
    Samuel D. Kingsland

/s/ WILLIAM H. LANE III              .                    Director                              August 24, 2001
-------------------------------------------------------
    William H. Lane III

/s/ RODERICK C. MCGEARY                                   Director                              August 24, 2001
-------------------------------------------------------
    Roderick C. McGeary
5

                                INDEX TO EXHIBITS
EXHIBIT NUMBER                      EXHIBIT DOCUMENT
-------------------   ---------------------------------------------
      5.1             Opinion of Counsel

     23.1             Independent Auditor's Consent

     23.2             Consent of Counsel (contained in Exhibit 5.1 hereto)

     24.1             Power of Attorney (see signature page)