FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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(Print or Type Responses)

1. Name and Address of Reporting Person * ONEILL PATRICIA   2. Issuer Name and Ticker or Trading Symbol ART TECHNOLOGY GROUP INC [ARTG] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) SVP, Human Resources (Last) (First) (Middle) ONE MAIN STREET 3. Date of Earliest Transaction (Month/Day/Year) 05/12/2008 (Street) CAMBRIDGE, MA 02142 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 05/12/2008   M   15,000 (1) A $ 0 15,000 D

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Restricted stock units

(2)

05/12/2008

M

7,500

(3)

(3)

Common Stock

30,000

$ 0

22,500

D

Restricted stock units

(2)

05/12/2008

M

7,500

(4)

(4)

Common Stock

30,000

$ 0

22,500

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
ONEILL PATRICIA ONE MAIN STREET CAMBRIDGE, MA 02142			SVP, Human Resources

Signatures

/s/ Jeffrey T. Kowalski, by Power of Attorney		05/14/2008
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Represents shares issued upon the vesting of restricted stock units.
(2)	Each restricted stock unit represents a contingent right to receive one share of Art Technology Group, Inc. common stock.
(3)	The restricted stock units vest in four equal annual installments beginning May 12, 2008 and annually thereafter.
(4)	The number of restricted stock units that may vest is determined by the performance metrics set forth in the applicable restricted stock unit agreement. Of that subset of restricted stock units that may vest, the restricted stock units vest in four equal annual installments beginning May 12, 2008 and annually thereafter; provided, however, that additional performance metrics set forth in the applicable restricted stock unit agreement may trigger immediate vesting in full.

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