They are taking down youtube, xbox live, ect not because they did anything to anon, its becaue it will get the most commercial response. Millions of americans use these things and with them down they will go bonkers over wtf. A normal person won't care if UN or CBS or ect are hacked.
Its like the blackouts that recently happened. Did i notice google put a black banner over their logo? hell no, that was weak. Did i notice when sites like wikipedia were not working and blacked out. hell yes.
Same reason to hack xbox live or youtube. People will notice. People get mad, people contact repesentatives and bitch.