I also have a more general point to make.
I am quite confused about sharing items via Microsoft products over the internet. Here is a partial list of technologies available to share files from Microsoft: Good old Windows shares, Groove folder share, www.foldershare.com, Windows Messenger 8, you might also argue Sharepoint with offline support via 1) Groove 12 and 2) offline support within Outlook, then you can share stuff via Exchange folders and I am sure I have missed some. They are all named quite similiar, and unless two geeks want to share stuff it is almost certain that it will take a lot time to communicate which sharing technology should be used in a particular scenario. I think there should be ONE concept of sharing items in Windows that works across all those scenarios. One UI. Consolidation is required, I believe. Right now I have the impression that MS is creating more and more technologies, instead of unifying them, which would really be needed.
I was so glad to read your post..I've also been wondering about this exact same issue..I use all of the services you mentioned and was wondering too if they plan to unify them all as some Live service here eventually.