The Real Geek Squad: Fighting terrorism with your slide rule.

Geeks can be fierce.

mt1124997273.jpgVia Cyber-spies tracking terrorists through the web.

 Resembling a modern-day Clark Kent, Weisburd is a boyish 40-something former computer programmer who decided to use his background and skills to track terrorists following the terrorist attacks of 9/11.

He's proved himself a force to be reckoned with, fighting -- and winning -- a war waged against the "dark side" of the Internet.

To do this, Weisburd poses as a member of the Islamic Brotherhood, using what he's learned from al Qaeda's terrorist networks to glean information and then pass it on to the appropriate people -- whom he calls "associates."

These "associates", says Weisburd, may or may not necessarily be affiliated with law enforcement.

To emulate and catch the bad guys, Weisburd adopts their language and behavior, noting that it's rare to be kicked out of a terrorist community forum for being "too radical."

"If somebody reports on the latest terror attack, then the Brothers usually think that's a cool thing, so they'll respond with praise for the bombers. That would be appropriate behavior," says Weisburd.

Weisburd's reputation has earned him the nickname "the vigilante" in cyber space, a legacy he's eager to shrug off.

"If I was a vigilante running a Web site, I would hurt you," says Weisburd.

"If I find that you're running a Web site for al Qaeda, I'm not going to hurt you. I'll report you to people that will ask you to come quietly, and if you don't go quietly, they may hurt you," he says.