Windows Server System Magazine- The Future of Microsoft Collaboration: "If you've tracked Microsoft's collaboration technologies over the past several years, its strategy might seem less than complete or even inconsistent. Exchange 2000 included conferencing and instant messaging capabilities and seemed to set the server up as the collaboration tool. However, today, Exchange 2003 has returned to its roots as a messaging platform and new products are in development that provide expanding conferencing and IM services. That might leave you wondering how SharePoint fits into the picture. The strategy might appear to be in disarray, but a closer look will reveal a compelling plan emerging from the chaos."
FYI my perspective on Microsoft's collaboration strategy. Note: the Groove white paper referenced in the article will be posted in a week or two, and I'll post a reference here when it is; FTP posted the collaboration article earlier than I expected (it's in the Nov issue of "Windows Server System" -- formerly .NET Magazine).