I was scouting around to find a solution to my current spam overload (I currently use Cloudmark's Spamnet but it only runs on a client) and I came across this I just think it's really interesting that MS is planning to address the Spam plague in such a proactive way - and at long last!
The real pain in the butt though is this:
Intelligent Message Filter, scheduled for release in 2004, will be available exclusively to customers enrolled in Software Assurance. If your Exchange servers and associated client access licenses (CALs) are enrolled in Software Assurance (SA) when Intelligent Message Filter is released, you will be eligible to receive one complimentary license for the Intelligent Messaging Filter software for each Exchange server license that you have enrolled in SA. To receive a complimentary license for Intelligent Messaging Filter, make sure that your company is eligible. Your SA benefits coordinator can verify your company’s eligibility by visiting the Microsoft Volume Licensing Services site.
Why are they doing this? It's my belief that the more Spam removal tools are used then the less profitable Spam will become...go on, make it free and make it widely available!