The Web Forces a Radical Overhaul of Exchange

Microsoft released the first version of Exchange, Exchange 4.0, in Mar. 1996 as a messaging (e-mail) and collaboration server. Although Exchange has never enjoyed overwhelming success in the collaboration marketplace and still trails Lotus Notes/Domino, it has gained a huge following as an e-mail server. Exchange 4.0 won early acceptance because it inherited a significant Microsoft Mail–installed base and because the highly functional Outlook 97 e-mail client was part of the standard corporate desktop, Microsoft Office. Later releases of Exchange-in particular version 5.5 Service Pack 1 (SP1)-earned significant market share on their own merits. Recent estimates indicate that Exchange has won more than 34 million seats since its initial release.

This success came in spite of some significant deficiencies. The initial design of Exchange suffered from scalability and manageability limitations that made it difficult to support, particularly in large companies. A typical Exchange 5.5 server supports fewer than 1,000 users, and the largest multiple-processor servers available are hard pressed to handle more than a few thousand users. Fortune 500 companies and government agencies who needed to provide Exchange access to hundreds of thousands of users found that they had to manage a complex infrastructure with hundreds of Exchange servers. Burdened by such scalability issues, Exchange never achieved any significant penetration in the Internet service provider (ISP) marketplace, one that has become critical in the past two years.