I've just added descriptions and notes to docs.communityserver.org regarding some of the changes in CS2007.1 (previously known as SP3) I was involved with:
All of these changes and many more are available in the CS2007.1 update.
Read the complete post at http://feeds.feedburner.com/~r/BenTiedt/~3/149351001/some-notes-about-community-server-2007-sp3.aspx