ATG and Steria Announce Today a Wide Ranging Partnership Agreement Focused Upon Delivering Consulting and Services in Support of ATG's European Business

Peter Ford, ATG Alliances Director for Europe, Middle East &Africa said, "We're delighted to have secured the services of Steriato assist in delivering our solutions across Europe. The partnershipwill offer Steria customers the opportunity to extend their existingCRM infrastructure and significantly enhance online customerexperience and support services using ATG's solutions."

Gilles Graziani, Director at Steria said, "We see this alliancewith ATG as a strategic decision to provide our clients withtime-to-market world class solutions in customer experience andselfcare. ATG's solutions will help our clients to better understandhow end users interact with the business at every touch point andallow them to improve the potential value of every customerinteraction, whether it is an outbound marketing campaign, a commercetransaction, or a request for service support. This partnership bringsreal value in our Client - Facing set of solutions and we are excitedto working with ATG across Europe."

About Steria (www.steria.com)

Extensive expertise in its three core businesses of consulting,systems integration and managed services has made Steria a leadingend-to-end IT services provider for companies and public authoritiesthroughout Europe. With a revenue of EUR 1.2 billion and 9,300employees, Steria is one of the top ten European IT servicescompanies.

Understanding the challenges facing its customers enables Steriato design business-specific solutions with high added value in all ofits fields of expertise - the public sector, healthcare,banking/insurance, telecommunications andutilities/transport/manufacturing - as well as innovativetechnological solutions. Based on over 35 years' experience inmanaging large-scale projects, an exceptional ability to respond andan industrial approach to business, Steria has developed aresult-based culture with a commitment to service quality and customersatisfaction. Steria's employees, who hold 24% of the Group's capital,draw on its core values of simplicity, creativity, independence,respect and openness to transform the latest technology intoadded-value services, enabling Steria to help its customers achieveand maintain competitive advantage. Steria is listed on EuronextParis, Eurolist (Compartment B).

About ATG

ATG (Art Technology Group, Inc., NASDAQ: ARTG) makes the softwarethat the world's most customer-conscious companies use to create amore relevant and consistent customer experience, throughout themarketing, commerce, and service lifecycle, and across the Web,e-mail, call center, and mobile channels. Offering an alternative tothe traditional silo-based approach to customer-facing applications,ATG Wisdom(TM) is the company's strategy for delivering a seamless,more compelling, and mutually valuable experience to each customer andsegment. The company fulfills this strategy by providing fullyintegrated best-of-breed product suites installed on-premise ordelivered on-demand. ATG's solutions power over 600 major brands,including A&E Networks, Airbus, American Airlines, American EagleOutfitters, Best Buy, Boeing, Cingular Wireless, DirecTV, FranceTelecom, Friends Provident, Hewlett-Packard, Hotels.com, Hyatt Hotels,HSBC, InterContinental Hotels Group, Kingfisher, Louis Vuitton,Merrill Lynch, Neiman Marcus, Philips, Procter & Gamble, Symantec,T-Mobile, Target, US Army, US Navy, Warner Music, and Wells Fargo. Thecompany is headquartered in Cambridge, Massachusetts, with additionallocations throughout North America and Europe. For more informationabout ATG, please visit www.atg.com.

(C) 2006 Art Technology Group, Inc. ATG and Art Technology Groupare registered trademarks, and ATG Wisdom is a trademark of ArtTechnology Group, Inc. All other product names, service marks, andtrademarks mentioned herein are trademarks of their respective owners.

This press release contains forward-looking statements forpurposes of the safe harbor provisions under The Private SecuritiesLitigation Reform Act of 1995. These statements involve known andunknown risks and uncertainties that may cause ATG's actual results,levels of activity, performance or achievements to be materiallydifferent from any future results, levels of activity, performance orachievements expressed or implied by such forward-looking statements.Important risk factors affecting ATG's business generally may be foundin its periodic reports and registration statements filed with theSecurities and Exchange Commission at www.sec.gov . Risk factorsrelated to the subject matter of this press release include thepossibility that the ATG product deployment will not be successful, ontime or significantly enhance the user's Internet experience or willnot increase customer revenue across brands; that those customersleveraging ATG will not have the opportunity to increase revenue anddecrease future costs; the need to adapt to rapid changes so productsdo not become obsolete; the possibility of errors in ATG's softwareproducts; the possibility that the solution will not make customerimplementations faster or more flexible or permit the customer to meetits customer-facing or infrastructure requirements; that the ATGproduct will not continue to be integrated with third partyapplications servers or will not support all Web services enabledsystems; that ATG's product strategy may change in the future; and therisks and costs of intellectual property litigation. ATG undertakes noobligation to update any of the forward-looking statements after thedate of this press release.