As always Eileen finds cool stuff on Exchange and other MS products. Here she links to a series of articles on our internal deployment of Exchange 2007 and I found the one on our shift to an entirely 64bit based deployment the most interesting in terms of what it gives us. As you probably know, Exchange 2007 is 64 bit only and this is a great article for those of us (i.e. me) who need a quick primer on this.
Short story: this is saving us $5m per year!
Favourite line: The 64-bit platform supports eight Terabytes of user-mode memory and another eight Terabytes of kernel-mode memory. These memory limits practically eliminate all issues related to virtual memory fragmentation or shortage of kernel resources. With such high memory limits, a 64-bit Exchange server has a large pool of system resources available to handle theoretically a very large number of concurrent client connections
Interesting Stats: Over 13m Internet submitted emails per day with over 10.5m blocked submissions