It seems I just made a storm of improvements but here are some more.
- You can now add your Gamertag to your profile. New users can do this at registration, and current users can click on "User control Panel" in the somewhat-upper (heh) left menu (ie., "User Control Panel (0 new messages) • View your posts")
- You can now add your twitter ID as well via the same process.
- Every topic now has the option to share that topic with external social networks such as facebook, myspace, orkut, twitter and more. Simply look at the top of the first post in that topic where you normally would find the edit button if your the author, and you will find the related icons.
There were a few more changes but they are all back-end to improve performance.