USi Announces Innovative Exchange 2000 Technology Evaluation Tool; Corporate Customers Can Now Easily Evaluate Microsoft Exchange 2000 Server Via ASP Service Offering

Business Wire, June 5, 2000

Business/Technology Editors

Microsoft TechEd

ORLANDO, Fla.--(BUSINESS WIRE)--June 5, 2000

USinternetworking Inc. (USi, Nasdaq:USIX), the leading Application Service Provider (ASP), and the first ASP to deliver Microsoft Exchange 5.5 as a hosted enterprise software solution, today announced an innovative technology evaluation tool, the E2K Test Drive Server(SM), designed to assist enterprise customers in managing the enhanced features and functionality of the Microsoft Exchange 2000 Server. USi, a silver sponsor of Microsoft's Exchange 2000 product launch, also announced a series of strategic Exchange 2000 marketing initiatives in support of its continued relationship with Microsoft.

The E2K Test Drive Server runs on USi's robust messaging platform and enables enterprise customers to leverage USi's ASP delivery model to test and evaluate the enhanced messaging and collaboration features of Microsoft's Exchange 2000 Server. A main feature of the E2K Server includes the greatly improved Outlook Web Access (OWA) client.

Nick Magliato, President and General Manager of USi's Enterprise Messaging & Collaboration Business Unit said, "With this one-of-a-kind tool, USi and Microsoft can enable companies of all sizes to test the powerful features and functionality of Exchange 2000 with no impact on the customer's current messaging environment. Best of all, this tool simultaneously enables customers to experience the convenience and performance of hosted Exchange solutions from USi."

"Enterprise customers are excited about Exchange 2000, and want to easily evaluate its new features for messaging and collaboration," said Russ Stockdale, Vice President of the Knowledge Worker Solutions Group at Microsoft. "USi's E2K Test Drive Server lets IT professionals experience the benefits of new features like instant messaging, unified messaging, and the web storage system without the need to install software and tie up scarce resources."

USi has also allied itself with several leading Microsoft solution providers, including Visalign and ePresence to deliver the desktop integration services necessary to help enterprise customers migrate from legacy platforms to Microsoft Exchange. Additional initiatives on the part of USi include working with Microsoft District Offices to conduct direct marketing campaigns targeting customers with legacy messaging platforms, as well as existing Exchange 5.5 customers with an immediate interest in testing the features of Exchange 2000.

Live demonstrations of the E2K Test Drive Server will be available throughout TechEd at the USi booth, #443, located in the Microsoft Pavilion. Additionally, Mr. Spyros Sakellariadis, USi's Vice President and Chief Technology Officer for Enterprise Messaging, will conduct a live demo of hosted Exchange 2000 during his panel presentation entitled "Best Practices for Hosting Exchange 2000." Separately, interested enterprise customers can engage USi to develop custom demo environments for the purpose of testing Exchange 2000 for a number of products and devices. If interested, please call Matt Howard at (703) 883-4903.

About USinternetworking, Inc.

USinternetworking Inc. (Nasdaq:USIX) is a leading Application Service Provider delivering e-commerce and enterprise software as a service. The Company's iMAP portfolio of service offerings delivers the rich functionality of leading software from Ariba, BroadVision, Lawson, Microsoft, Niku, Oracle, PeopleSoft, and Siebel as a continuously supported, flat rate monthly service via an advanced, secure global data center network. For more information, visit www.usi.net.

Internet Managed Application Provider, iMAP, AppHost, PriorityPeering, USiGSP, USiSAN UsiAccelerate,and Making Software Simple are service marks of USinternetworking, Inc. All other trademarks are the property of their respective owners. USi strategic partners and providers are publicly traded on Nasdaq under the symbols: ARBA, BVSN, CSCO, MSFT, NIKU, ORCL, PSFT and SEBL.

Information in this release may involve expectations, beliefs, plans, intentions or strategies regarding the future. These forward-looking statements involve risks and uncertainties. All forward-looking statements included in this release are based upon information available to USinternetworking Inc. as of the date of the release, and we assume no obligation to update any such forward-looking statement. The statements in this release are not guarantees of future performance and actual results could differ materially from our current expectations. Numerous factors could cause or contribute to such differences. Some of the factors and risks associated with our business are discussed in the Company's registration statement on Form S-1 declared effective by the Securities and Exchange Commission ("SEC") on April 8, 1999, the Company's Form 10-Q filed with the SEC on May 15, 2000, and in our other reports filed from time to time with the SEC.