To mark their thousandth tweet, the prank-happy hackers at Lulz Security have posted a manifesto of sorts on Pastebin. Normally, we would give you a brief background on the group, but theirs is funnier: 

For the past month and a bit, we've been causing mayhem and chaos throughout the Internet, attacking several targets including PBS, Sony, Fox, porn websites, FBI, CIA, the U.S. government, Sony some more, online gaming servers (by request of callers, not by our own choice), Sony again, and of course our good friend Sony.
Most of the group's attacks so far have seemed random or pointless, aside from giving them the lulz (Internet speak for laughs) they've said are the only reason they're in the hacking game. But with today's missive, the group leaves the random prankster category and enters the activism camp, simply because its members do, it seems, have a point to make after all. Basically, they're here to show you how flimsy security is, all over the Internet.
Do you think every hacker announces everything they've hacked? We certainly haven't, and we're damn sure others are playing the silent game. Do you feel safe with your Facebook accounts, your Google Mail accounts, your Skype accounts? What makes you think a hacker isn't silently sitting inside all of these right now, sniping out individual people, or perhaps selling them off? You are a peon to these people. A toy. A string of characters with a value.
 
This is what you should be fearful of, not us releasing things publicly, but the fact that someone hasn't released something publicly. We're sitting on 200,000 Brink users right now that we never gave out. It might make you feel safe knowing we told you, so that Brink users may change their passwords. What if we hadn't told you? No one would be aware of this theft, and we'd have a fresh 200,000 peons to abuse, completely unaware of a breach.
Whether you think they make a good argument or can't forgive them for knocking out EVE Online, at least the explanation is out there. LulzSec is on the record as not just in it for the lulz.