ATG and Sapient Extend Strategic Partnership.

Alliance Unites Premium E-commerce Software and Services with Unmatched Design and Implementation Capabilities to Build Personalized Web Experiences

CAMBRIDGE, Mass. -- ATG (Art Technology Group, Inc., NASDAQ: ARTG), the top-ranked e-commerce platform and optimization services provider, and global services firm Sapient (NASDAQ: SAPE), today announced the formalization of the companies' strategic partnership. The two companies already have been working closely together on e-commerce and Web marketing projects for many of the world's leading brands. The foundation of success built from these experiences has quickly evolved into an industry leading joint value proposition for delivering highly differentiated on-line and multi-channel experiences to the retail, consumer goods, media and telecommunications marketplaces.

From strategy to tactics, design to deployment, marketing to management, ATG and Sapient bring a comprehensive approach to delivering e-commerce solutions that drive increased revenue, greater operational efficiency and improved customer loyalty. Sapient's interactive marketing and consulting teams are currently working on ATG engagements throughout the United States, Canada, Great Britain, Germany and India.

"ATG and Sapient have a proven track record, helping myriad companies achieve tremendous growth on the Web," said Drew Reynolds, senior vice president of corporate development for ATG. "Our offerings and customer base complement each other, and by extending our partnership into our target markets globally, it will enable us to more quickly and easily bring our combined strengths to bear for customers worldwide."

"We continue to see an unprecedented market demand for more customized multi-channel online experiences and advanced e-commerce initiatives worldwide," said Chris Davey, senior vice president, Sapient. "Our clients seek partners who can help them implement better tools and techniques for driving higher conversion rates, increased traffic and greater share of wallet. Furthermore, they look to us to create highly differentiated online and multi-channel experiences that drive growth in their businesses. We find that ATG's e-commerce platform and our deep knowledge of how to apply it to improve overall marketing, merchandising and multi-channel sales are a powerful combination."

In 2008, Sapient has significantly increased the number of developers and architects who are ATG certified and the company already has an impressive global team of technology implementation experts in place who are trained and experienced with ATG's suite of e-commerce software products.

The ATG Commerce Suite is a set of flexible, component-based e-commerce software applications that enable merchants to personalize the online buying experience for their customers, making it easy for them to find desired products, comparison shop, register for gifts, pre-order products, redeem coupons and execute many other useful features. In the most recent Forrester Wave[TM]: Commerce Platforms report,1 Forrester Research ranked ATG's B2C e-commerce software suite as the number one current offering. Gartner, Inc. also positioned ATG in the "Leader" quadrant in its most recent E-Commerce Magic Quadrant report.2

About Sapient

Sapient, a global services firm, helps clients compete, evolve and grow in an increasingly complex marketplace. Sapient Interactive provides brand and marketing strategy, award-winning creative ,web design and development and emerging media expertise. Sapient Consulting provides business and IT strategy, process and systems design, package implementation and custom development, as well as outsourcing services such as testing, maintenance and support.

Sapient's passion for client success--evidenced by its ability to foster collaboration, drive innovation and solve challenging problems--is the subject of case studies on leadership and organizational behavior used by MBA students at both Harvard and Yale. Leading clients including Harrah's Entertainment, Sony Electronics, Staples, Vodafone, Royal Mail and Barnes and Nobles College Booksellers rely on the company's unique approach to drive growth and market momentum. Headquartered in Cambridge, Massachusetts, Sapient operates across North America, Europe and India. For more information, please visit http://www.sapient.com.

About ATG

ATG (Art Technology Group, Inc., NASDAQ: ARTG) provides the e-commerce platform and e-commerce optimization services that the world's most customer-conscious companies use to power their e-commerce Web sites, attract prospects, convert them to buyers and ensure their satisfaction so they become loyal, repeat, profitable customers. Our e-commerce suite is ranked the #1 current offering and #1 in strategy by the industry's most influential analyst firms, and powers more of the top 300 internet retailers than any other vendor. Our eStara brand of e-commerce optimization services - including the world's most widely used click to call offering - dramatically increase conversions and order size and enhance customer support. ATG's solutions are used by over 900 major brands, including AT&T, Best Buy, Bulgari, Coca Cola, Continental Airlines, CVS, Dell, Diane von Furstenberg, DirecTV, eLuxury, El Corte Ingles, Expedia, 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, Vodafone and Walgreens. For more information, please visit http://www.atg.com.

(c) 2008 Art Technology Group, Inc. ATG and Art Technology Group are registered trademarks, and ATG Wisdom is a trademark of Art Technology Group, Inc. 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.