The "vigilante justice" stuff that's branded as "Anonymous" is from 2008ish. Before that, "anonymous" was a group only insofar as its "members" were unified by the fact that they were anonymous posters on 4chan. That was the only unifying feature of it. The idea of a "group" was mostly a running joke about some of the pretty twisted attitudes that people took when liberated from any sort of identity.
The reason anonymous was important, whether anyone even realized it, was that it was one of the first times when people were completely free to speak their mind on any significant scale. People were able to say anything they thought, no matter how awful or out there it might be or what other people might think. The only repercussions were the responses of others; what you said would be scrutinized, and if it didn't make sense, someone would eventually say so. This is probably more important than anyone could ever realize, and I could go on for pages about what it did for those involved, why it works, and its effects (the most obvious of which is the extremely rapid rate of cultural evolution noted by sociologists in recent years). It's probably one of the reason moot still operates 4chan despite having lost a lot of money on it; I think he understands its significance, at least to some extent.
Anyway, this whole "Anonymous" vigilante thing clouds something that's much bigger and that people really need to see and understand. And that's what makes me sad.
Also, on another note, Planescape: Torment is pretty fantastic.
There's no such thing. Anonymous isn't a group, it's the idea of ultimate free speech. Anyone can be or not be anonymous at any time, including people with completely conflicting goals. I could make a completely opposite statement to what you saw and be equally as "official," because there's no such thing as official. It's a bit sad that nearly a decade later, people still just don't get it (or worse, are actively subverting the idea).
I guess the most likely reason I didn't get it was because I don't usually pay much attention to them.