The b variant (Mydoom.b) failed it’s DoS (Denial of Service) payload on Microsoft’s Web site today due to it being less widespread than the original worm.
I use AIM as my primary IM program because most of my friends use it. I also use MSN and Yahoo! Messenger but I don’t use them as often because not many people that I know use those IM programs. I’ve used DeadAIM and AIMutation for cloning since my brother uses my PC sometimes.