Windows Server System Magazine: Microsoft's Expanding Collaboration Strategy: "The enterprise markets for communication and collaboration products and services are in the midst of a major transition. 'The Future of Microsoft Collaboration' [November 2003] provided an overview of Microsoft's collaboration and communication strategies and products at the end of 2003. This column updates you on the market dynamics and Microsoft's progress since then."
FYI my January, 2005 column. Note that Microsoft changed the schedule/strategy for Exchange Edge Services after the article was published; it's now split between 2005 and the next major release of Exchange Server.