Anon started out doing pretty silly things, too, I believe, and soon their mission "matured" and became more serious. I'm starting to feel the same trend for LulzSec, and they even said so in a very recent BBC interview. They were asked if the "lulz" and the "antisec" missions are at odds with each other. They said for now they will keep doing a bit of each, but they think they'll start getting more serious as it's more fulfilling to have a cause like bringing down a few notches the corrupt officials, etc.

So we'll see if that's what will happen. They are pretty unpredictable, but I think they'll get caught up in this and continue doing it for the good of everyone.