ATG and imc(2) Announce Partnership to Deliver Sophisticated E-Commerce Services on Demand.

Combination of Teams' Services Enables Retailers to Move from Homegrown Solutions to Top-Rated Platform

CAMBRIDGE, Mass. -- ATG (Art Technology Group, Inc., NASDAQ: ARTG) and imc(), an independent full-service digital marketing agency, today entered into a strategic partnership to provide growing retailers with the opportunity to move from home-grown e-commerce solutions to a top-rated, robust platform that enables the development of more sophisticated, scalable online storefronts. Under terms of the partnership agreement, imc() is currently the only Top 10 interactive agency providing ATG OnDemand to power e-commerce sites and corresponding e-marketing and customer services through a subscription model.

"Recently, we've observed that more retailers want to get serious about sophisticated e-commerce earlier in their growth processes," said Cliff Conneighton, senior vice president, ATG. "As a result of partnering with imc(), we're helping online sellers of all sizes take advantage of the sophisticated features that have made ATG's platform the highest-rated in the industry. ATG offers the highly robust functionality and flexibility that serious businesses are seeking, and this partnership makes switching to ATG a realistic option for almost anyone."

The ATG-imc() partnership is designed to combat the scalability, efficiency and customization challenges facing retailers that operate home-grown or less functional outsourced solutions. By teaming with ATG and imc, retailers who are moving to a second-generation platform can now receive a feature-rich, highly customized Web presence that better represents their company brand, drives conversion and extends customer intimacy.

"We are excited to be the first major online marketing agency offering the power of ATG's OnDemand technology to retailers whose growth has been inhibited by the limitations of the platforms they currently use," said Mike Graziano, director of retail e-commerce at imc. "We understand retailers' need to drive conversion, as well as average order value and frequency-of-purchase with existing customers, and those are all areas that ATG excels in. We look forward to helping retailers achieve their growth objectives by arming them with the strategies and tools that will take their businesses and brands to the next level."

Currently, imc()provides retail customers with services ranging from initial strategy to tactical implementation, including e-commerce platform implementations, user experience designs, relationship marketing programs, search engine marketing/optimization, online media and promotions, hosting and managed services and ROI measurement tools. ATG's platform, recently ranked No.1 by Forrester Research among current business-to-consumer e-commerce offerings, adds a new dimension to imc()'s capabilities by providing a solution that grows in step with businesses and allows merchants to move to alternative ownership models as their organizations expand and evolve.

About ATG

ATG (Art Technology Group, Inc., NASDAQ: ARTG) makes the software and delivers the on demand solutions 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. ATG's B2C e-commerce suite is ranked the #1 current offering by Forrester Research, and powers more of the top 300 internet retailers than any other vendor. ATG's solutions are used by over 600 major brands, including Adobe, A&E Networks, American Eagle Outfitters, B&Q, Best Buy, Cingular Wireless, Coca Cola, Dell, DirecTV, France Telecom, Hewlett-Packard, Intuit, Johnson & Johnson, Louis Vuitton, Mercedes-Benz, Neiman Marcus, New York & Company, Nike, Nokia, OfficeMax, PayPal, Philips, Procter & Gamble, Rubbermaid, Smith & Hawken, Symantec, T-Mobile, Target, Verisign, and Walgreens. The company is headquartered in Cambridge, Massachusetts, with additional locations throughout North America and Europe. For more information about ATG, please visit www.atg.com.

About imc

imc - an independent digital marketing agency - is dedicated to helping its clients achieve their business objectives through interactive marketing. Recently ranking in the top 10 on Advertising Age's "Top 50 Interactive Agencies," imc has offices in New York, Dallas, Philadelphia and Cincinnati. imc has more than 300 employees and provides interactive services in the following areas: strategy and insight, media and promotions, Web development, relationship marketing, and measurement and intelligence. imc serves a broad and diversified global client base, including Procter & Gamble, Johnson & Johnson and Pfizer. Please visit www.imc2.com for more information.

(c) 2006 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 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; 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.