This is a great news, TeamPlain are the leader in Team System web access as a group (MVPs and influencer) we told Microsoft "if you are going to provide web access to TFS, make it better then TeamPlain of buy them", looks like the listen to us ;-). What is also great about this news is they will be able to spend more cycle on new features in TFS and just gain a whole web access platform which is good for everyone.
Nice move Microsoft read all about it here on Brian's blog.
Cheers,
ET