ATG Positioned in the Leaders Quadrant for e-Commerce Magic Quadrant

Evaluation Based on Completeness of Vision and Ability to Execute

CAMBRIDGE, Mass. - August 19, 2008 - ATG (Art Technology Group, Inc., NASDAQ: ARTG), the premier provider of e-commerce software and platform neutral optimization services, today announced that it has been positioned by Gartner, Inc. in the leaders quadrant in the Magic Quadrant for E-Commerce. Published by Gartner research vice president Gene Alverez on July 18, 2008, the report included ATG as one of the technology providers in the Leaders quadrant that has "demonstrated longevity in the e-commerce market, as well as a commitment to new product innovations for Internet sales. In addition, leaders represent technology providers with the strongest capability to meet Internet selling requirements."¹

To be included in this report, technology vendors must meet certain criteria regarding their e-commerce product capabilities, short term viability and market traction and momentum. In an explanation of standards used to determine which companies are placed in the leaders quadrant, the report cites the following:

"This quadrant contains technology providers that demonstrate the greatest degree of support for B2B and B2C Internet sales. These providers lead the market in e-commerce by consistently demonstrating customer satisfaction, strong support and professional services, leading to the implementation of a successful e-commerce site. Technology providers in this quadrant have demonstrated consistent, extensive and durable execution in delivering e-commerce Web sites at the enterprise level. In addition, the maturity of this market demands that leaders maintain a strong vision regarding the key points that have emerged during the past year - such as, but not limited to, Web 2.0 (user experience and community capabilities), multiple deployment options and multisite management; the capability to support B2B, B2B2C and B2C selling models; integration with multiple points of interaction, such as mobile, call centers and stores, and supporting overall sales, service and marketing in an e-commerce context."¹

"We believe inclusion in the leaders quadrant is not only an exciting honor, but it is also a proven testament to ATG's standing in the e-commerce industry," said Bob Burke, president and CEO, ATG. "Demand for experienced e-commerce solutions throughout the industry is higher than ever, proving that customers are investing in their online capabilities."

About the Magic Quadrant

The Magic Quadrant is copyrighted 2008 by Gartner, Inc. and is reused with permission. The Magic Quadrant is a graphical representation of a marketplace at and for a specific time period. It depicts Gartner's analysis of how certain vendors measure against criteria for that marketplace, as defined by Gartner. Gartner does not endorse any vendor, product or service depicted in the Magic Quadrant, and does not advise technology users to select only those vendors placed in the "Leaders" quadrant. The Magic Quadrant is intended solely as a research tool, and is not meant to be a specific guide to action. Gartner disclaims all warranties, express or implied, with respect to this research, including any warranties of merchantability or fitness for a particular purpose.

About ATG

A trusted, global specialist in e-commerce, ATG (Art Technology Group, Inc., NASDAQ: ARTG) has spent the last decade focused on helping the world's premier brands maximize the success of their online businesses. The ATG Commerce application suite is the top-rated platform for powering highly personalized, efficient and effective e-commerce sites. The company offers a line of platform-neutral, SaaS-based ATG e-commerce Optimization Services, which can be easily added to any Web site to increase conversions and order size. ATG customers include progressive, innovative online brands like AT&T, Best Buy, Bulgari, Coca Cola, Continental Airlines, CVS, Dell, Diane von Furstenberg, DirecTV, eLuxury, El Corte Ingles, France Telecom, Harvard Business School Publishing, Hewlett-Packard, Hilton, HSBC, Intuit, Jenny Craig, Louis Vuitton, Macy's, Mercedes Benz, Meredith, Microsoft, Neiman Marcus, New York & Company, NutriSystem, OfficeMax, PayPal, Philips, Procter & Gamble, Sears, Sony, Symantec, Target, T-Mobile, Tommy Hilfiger, Urban Outfitters, Verizon, Viacom, and Vodafone. For more information, please visit http://www.atg.com.

¹Gartner "Magic Quadrant for E-Commerce" by G. Alvarez. July 18, 2008.

2008 Art Technology Group, Inc. ATG and Art Technology Group are registered trademarks. All other product names, service marks, and trademarks mentioned herein are trademarks of their respective owners.

This press release contains forward-looking statements for purposes of the safe harbor provisions under The Private Securities Litigation Reform Act of 1995. These statements involve known and unknown risks and uncertainties that may cause ATG's actual results, levels of activity, performance or achievements to be materially different from any future results, levels of activity, performance or achievements expressed or implied by such forward-looking statements. Important risk factors affecting ATG's business generally may be found in its periodic reports and registration statements filed with the Securities and Exchange Commission at www.sec.gov. Risk factors related to the subject matter of this press release include the possibility that the ATG product deployment will not be successful, on time or significantly enhance the user's Internet experience or will not increase customer revenue across brands; that those customers leveraging ATG will not have the opportunity to increase revenue and decrease future costs; the need to adapt to rapid changes so products do not become obsolete; the possibility of errors in ATG's software products; the possibility that the solution will not make customer implementations faster or more flexible or permit the customer to meet its customer-facing or infrastructure requirements; that the ATG product will not continue to be integrated with third party applications servers or will not support all Web services enabled systems; that ATG's product strategy may change in the future; and the risks and costs of intellectual property litigation. ATG undertakes no obligation to update any of the forward-looking statements after the date of this press release.

Tucker Walsh
ATG
+1.617.386.1159
twalsh@atg.com