MELISSA BLOCK, host: If you've heard about a company being hacked or a website taken down, it's quite possible a mysterious group called Anonymous has taken credit for it.
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UNIDENTIFIED MAN: Do not mistake who we are for what we are and what we can do. Anonymous will fight. Anonymous will win.
BLOCK: That's a video posted by the group after they attacked the website of the Church of Scientology. Since then, the group has taken down the official government websites of Egypt, Tunisia and Iran, and the sites of credit card companies and police departments. We sent Zoe Chace of NPR's Planet Money to Las Vegas to track down Anonymous and find out how they do it and why.
ZOE CHACE: I went to a conference for computer hackers in Vegas. Turns out, people in Anonymous don't wear nametags. I did find some people who seem to know a lot about how they operate. They were at an all-you-can-eat Chinese buffet.
MERCEDES HAEFER: You're going to see me go through like 20 plates, because I just do all my food in like one day, and I'm good for the week. I'm like a snake.
CHACE: This is Mercedes Haefer. She's scrappy, got a purple ponytail and a sweet little face. She's 20, and she describes herself as a close observer of Anonymous. But even she couldn't give me the most basic fact I wanted to know about the group.
HAEFER: No one knows how many Anons there are because it's not like there's a census where everyone puts in their nickname and says, I'm an Anon, and then, you know, we count them all. People join and people go. And something big will happen, and people will join. And then that big thing is over, and they leave, and they never come back.
CHACE: Haefer is actually under indictment right now for an Anonymous attack on PayPal, so she's not allowed to use a computer. So she couldn't actually show me to the chatroom where Anonymous meets up on the Internet. But it's easy enough to find it on your own. There can be up to 600 people in one chatroom or channel just talking about the next Anonymous operation.
HAEFER: Someone walks into the channel and says, oy, mates, let's pick targets today. People shout targets. They say, oh, this happened recently, and this happened recently, and this happened recently. And it just gets added to the vote.
CHACE: It's an online poll, but instead of asking which band is better, which celebrity is hotter or something, it's more like, which company should we attack? But here's the tricky thing about Anonymous. People are always contradicting each other. I sat down with another observer of Anonymous, Rob Field. He's 23, and I asked him about the vote. Is there a vote?
ROB FIELD: No. No. Seriously, there's no vote.
CHACE: The way Field explains it, you don't need a vote. If you have an idea, you just go into the chatroom and say, who's with me?
FIELD: And people will be like, yeah, yeah, yeah, you know, I hate company X. Right? They charged me too much on my phone bill last month, whatever.
CHACE: When do you know that the conversation has landed on, like, this is what we're going to do, and it's not like people speculating anymore or coming up with ideas?
FIELD: It's about verbiage.
CHACE: Verbiage, meaning the verbs in the conversation actually shift from conditional tense to active tense.
FIELD: Oh, no. It would be cool if we - OK, so we're going to blank.
CHACE: The signature computer attack of Anonymous is to send massive amounts of traffic to a website, which basically shuts a site down. To do this, they use a botnet. It's a robot network of millions of compromised computers. And according to Field, you can actually buy one of these networks of computers online, at a site called the Russian Business Network.
FIELD: Those dudes sell everything. You want a mail-order bride, a botnet, some cocaine, some heroin, and you want a cheeseburger? Go see those guys.
CHACE: There are lots of sites like these hosted in other countries. And how much does a botnet go for these days?
FIELD: Five, 10 G.
CHACE: Five, $10,000 can buy you a decent botnet?
FIELD: Yeah, 5 to 10 G can get you some decent, decent power.
CHACE: People who believe in the cause often donate these computer networks called botnets. This past year, many of the Anonymous attacks have happened for free. Anyone who supports the cause can just turn their computer into an attack machine. Speaking of the cause, why are they doing this?
UNIDENTIFIED WOMAN: It's gone from freedom of information to like Egypt and Libya and Tunisia and Mexico and Spain...
FIELD: Oh, no. That's why I said freedom and freedom of speech and...
UNIDENTFIED WOMAN: It's just like what was done here was wrong.
CHACE: What Anonymous stands for is kind of up for grabs. I'm going to give the last word here to Rob Field.
FIELD: Everybody says everything is - oh, Anonymous, WikiLeaks; Anonymous, liberal (bleep). Anonymous this, that and the other, you know? I mean, I'm Republican. I'm conservative as all get out. But like, let's say, for instance, you want to join Anonymous and you say: I want to join Anonymous because of the fact that I agree with one of these things they're doing. OK, you're Anonymous. Right? Like, that's it.
CHACE: Right now, it's about transit cops in California. Next week, it could be something else entirely.
Zoe Chace, NPR News.
ROBERT SIEGEL, host: You're listening to ALL THINGS CONSIDERED from NPR News. Transcript provided by NPR, Copyright NPR.