One of the things revealed at BlizzCon 2009 was the new Battle.net 2.0. If you remember Starcraft 2 was delayed so Battle.net could be upgraded. New social features have been added along with many other tweaks including performance issues. Check out part 1 and part 2 of the Battle.net 2.0 Presentation below.
Battle.net 2.0 Presentation Part 1: