I meant to write about Windows Genuine Advantage communicating back to base every day when it was first announced, but first I wanted to check that blocking it did not hinder the monthly patch cycle—then I forgot. It happens a lot these days.
Anyway, the main problem was first reported at the beginning of the month. I blocked mine immediately and since then we have had Patch Tuesday and all went well.
As far as I can tell there is no need to allow WGA to contact the internet in its own right at all. It does its proper job via an ActiveX call from Windows Update which does the communication to verify that you have a good licence before allowing patch updates.
The sub-agenda function of sending a message back every day is not needed for anything so it is quite easy to block with an outgoing firewall like ZoneAlarm. Just look for the program under W and mark it forbidden for Internet. There is no need to use extra fancy programs like RemoveWGA.