We know what's going on now.
Here's how you can fix it for yourself - we will need to fix it permanently in a future version of the software, though.
Open the Zune software - sign in
Do NOT go to any social pages!
Leave the Zune software running for four hours
Close the software, then re-open and sign in again - we believe your friends will all be there.
Let me know if this doesn't work. the four hour part is really important - if you try in less than four hours, it won't work.
Jessica Zahn, Zune Social Program Manager ~ This posting is provided as-is with no warranties, and confers no rights.