<PAGE>

                                                                   EXHIBIT 10.85

              Equity Pledge Agreement-Participation Letter of Shenzhen E-Time

                   ACKNOWLEDGEMENT LETTER FOR PARTICIPATION OF
                             EQUITY PLEDGE AGREEMENT

JIMMY WEI YU (Identity Card Number: 310106731015081) and JASON NANCHUN JIANG
(Identity Card Number: 310109730305521) (hereinafter the "PARTICIPATED
PLEDGOR"), and SHENZHEN E-TIME COMMERCIAL CONSULTING CO., LTD. (registered
address: Room 802, Zhongdian Information Building, No. 1 Xinwen Road, Futian
District, Shenzhen) (hereinafter the "PARTICIPATED TARGET COMPANY"), hereby
agree to participate in Equity Pledge Agreement dated on March 28, 2005 between
Focus Media Technology (Shanghai) Co., Ltd. (hereinafter "FOCUS MEDIA
TECHNOLOGY"), Focus Media Digital Information Technology (Shanghai) Co, Ltd.
(hereinafter "FOCUS MEDIA DIGITAL"), Shanghai Focus Media Advertisement Co.,
Ltd. and other relevant parties (hereinafter the "EQUITY PLEDGE AGREEMENT") as
an independent contract party. The Participated Pledgor and the Participated
Target Company hereby agree to pledge the equity of the Participated Target
Company which constitute 100% of the registered capital of the Participated
Target Company to Focus Media Technology as of the date of this Acknowledgement
Letter to secure the following contractual obligations:

1.    Contractual Obligation for the Participated Pledgor:

(a)   Contractual Obligation under the Call Option Agreement among Focus Media
      Technology and other relevant parties dated March 28 2005 (hereinafter the
      "CALL OPTION AGREEMENT") participated by the Pledgor pursuant to the
      Acknowledge Letter executed by the Participated Pledgor on the date May
      22, 2006; and

(b)   Contractual Obligation under the Shareholder's Voting Rights Proxy
      Agreement among Focus Media Technology and other relevant parties dated
      March 28 2005 (hereinafter the "PROXY AGREEMENT") participated by the
      Pledgor pursuant to the Acknowledge Letter executed by the Participated
      Pledgor on the date May 22, 2006.

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              Equity Pledge Agreement-Participation Letter of Shenzhen E-Time


2.    Contractual Obligation for the Participated Target Company:

(a)   Contractual Obligation under the Call Option Agreement participated by the
      Target Company pursuant to the Acknowledge Letter executed by the
      Participated Target Company on the date May 22, 2006; and

(b)   Contractual Obligation under the Proxy Agreement participated by the
      Target Company pursuant to the Acknowledge Letter executed by the
      Participated Target Company on the date May 22, 2006.

This Acknowledgement Letter once executed by the Participated Pledgor and
Participated Target Company, the Participated Pledgor and the Participated
Target Company shall make the same undertakings and warranties with those of
Pledgors and Target Companies under the Equity Pledge Agreement (to the extent
that is related and applicable to Participating Shareholder and Participated
Target Company), agree to perform the obligations of Pledgors and Target
Companies stipulated in the Equity Pledge Agreement (to the extent that is
related and applicable to Participating Shareholder and Participated Target
Company), and admit the rights and obligations of Parties under the Equity
Pledge Agreement.

                   [THE REMAINDER OF THIS PAGE IS LEFT BLANK]

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              Equity Pledge Agreement-Participation Letter of Shenzhen E-Time

                                [EXECUTION PAGE]

JIMMY WEI YU

Signature by:     /s/ Jimmy Wei Yu
              ------------------------
Date: May 22, 2006

JASON NANCHUN JIANG

Signature by :    /s/ Jason Nanchun Jiang
              --------------------------------
Date: May 22, 2006

SHENZHEN E-TIME COMMERCIAL CONSULTING CO., LTD.
(Company chop)

Signature by:     /s/ Jason Nanchun Jiang
              -------------------------------
Name: Jason Nanchun Jiang
Position: Authorized Representative
Date: May 22, 2006

FOCUS MEDIA TECHNOLOGY (SHANGHAI) CO., LTD.
(Company chop)

Signature by:     /s/ Jason Nanchun Jiang
              --------------------------------
Name: Jason Nanchun Jiang
Position: Authorized Representative
Date: May 22, 2006

FOCUS MEDIA DIGITAL INFORMATION TECHNOLOGY (SHANGHAI) CO, LTD.
(Company chop)

Signature by:     /s/ Jason Nanchun Jiang
              --------------------------------
Name: Jason Nanchun Jiang
Position: Authorized Representative
Date: May 22, 2006