ATG Announces Three New OnDemand Solutions for Commerce And E-Service; New ATG OnDemand Solutions Harness the Power and Unique Advantages of ATG's Market Leading E-Commerce, E-Marketing, and E-Service Solutions - In a Hosted, Subscription Model Environment.

CAMBRIDGE, Mass. -- ATG (Art Technology Group, Inc., NASDAQ: ARTG), whose technology powers leading e-commerce sites and corresponding e-marketing and customer service, today announced the release of ATG Commerce OnDemand, ATG Answers OnDemand, and ATG Customer Care OnDemand, a suite of "software-as-a-service" solutions that provide unprecedented flexibility, convenience, and performance. ATG OnDemand service offerings deliver the identical software that analysts have ranked #1, and are used by world-class enterprises across the globe. ATG now offers these solutions through a subscription model, allowing companies to take advantage of the power of ATG e-commerce and e-service without investment in IT resources.

"ATG's OnDemand offerings are all about maximizing the power of ATG e-business solutions while minimizing operational burden" said Cliff Conneighton, senior vice president of marketing, ATG. "For companies with limited resources and time to dedicate to running commerce and e-service applications on premises, ATG Commerce OnDemand, ATG Answers OnDemand, and ATG Customer Care OnDemand are an ideal fit. Our solutions allow companies to focus on the business, not the technology used to run their business. Leaving the systems operations to ATG allows organizations to concentrate on the additional revenue, customer loyalty, and the cost savings our solutions bring to the table."

Unlike other vendors that provide only hosted offerings, ATG allows companies to move to alternative ownership models as a business grows and changes. For instance, if a customer's business becomes suited to owning the software license outright, the company can purchase software licenses and leave ATG to manage the infrastructure. Or, a company can take it all "in-house," and assume full ownership of the licenses and management. ATG OnDemand offers the flexibility needed to meet the needs of almost any organization, regardless of size or IT capability, that is serious about doing business on the web and satisfying its customers.

ATG OnDemand requires no investment in software licenses or maintenance agreements. Customers pay an initial setup fee, and after a very brief implementation period, the solution is running live at the ATG data center. Subsequent monthly payments are determined by application use.

ATG OnDemand solutions include:

--ATG Commerce OnDemand - A feature-rich, transactional Web presence for organizations to represent brand, display products, take orders, and reap the rewards.

--ATG Answers OnDemand - A self-service Web experience that delivers the right information to customers through the most convenient and cost effective medium possible - the Web.

--ATG Customer Care OnDemand - Customer self-service and Agent-assisted service, all in one complete solution. Provides the ability to tap into the hidden knowledge inside customer care organizations to ensure that customers and agents all have access to the same consistent set of information. Gives the ability to track, handle, and have better visibility into inquiries coming in to the customer care center. Further, provides the ability to manage the inquiries escalated from the self-service Web site.

About ATG

ATG (Art Technology Group, Inc., NASDAQ: ARTG) delivers innovative software to help high-end consumer-facing companies create a richer, more adaptive interactive experience for their customers and partners throughout the lifecycle of marketing, commerce, and customer service, and across the Web, e-mail and call centers. ATG has delivered category-leading e-business solutions to many of the world's best known brands including A&E Networks, American Airlines, AT&T Wireless, Best Buy, France Telecom, Friends Provident, Hewlett-Packard, InterContinental Hotels Group, Kingfisher, Merrill Lynch, Neiman Marcus, Philips, Procter & Gamble, Target, US Army, US Federal Aviation Administration, Warner Music, and Wells Fargo. The company is headquartered in Cambridge, Massachusetts, with additional locations throughout North America, Europe, and Asia. For more information about ATG, please visit www.atg.com.

(C) 2006 Art Technology Group, Inc. ATG and Art Technology Group are registered trademarks and ATG Commerce OnDemand, ATG Answers OnDemand, and ATG Customer Care OnDemand are trademarks 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 handle user volumes; that those customers leveraging ATG won't 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; that the hosting market will not grow or grow at the projected rates; 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.