The Internet attack took Yahoo engineers by surprise. It came so fast and with such intensity that Yahoo, then the Web's second most-popular destination, was knocked offline for about three hours.

That was on the morning of Feb. 7, 2000. A few months later, 15 year-old Michael Calce [cq] was watching "Goodfellas" at a friend's house in the suburbs of Montreal when he got a 3 a.m. call on his cell phone.

His father was on the line. "They're here," he said.

Calce knew right away what that meant. He had already talked to a lawyer after warning his father, weeks earlier, that he'd knocked offline a string of high profile Web sites -- Amazon, Dell, CNN -- and his attacks had been widely covered in the press.

Although the late-night visit by the Royal Canadian Mounted Police was not a surprise, Calce said his mind was racing as he walked out to a street corner to wait for a police cruiser to swing by and arrest him. What was going to happen? Would he go to jail?

Calce, who was known at the time only by his online moniker, Mafiaboy, eventually pled guilty to criminal hacking charges. He served time in a group home where he was allowed to attend school and a part-time job, but was otherwise essentially locked in his room. He couldn't use computers and, isolated from friends and family, he "almost hit a state of depression," he said in an interview this week -- one of his first since his arrest eight years ago.

"It changed me completely," he said of his time in detention. "I started to think about how I could help society rather than be a detriment."

To hear Calce tell it, it's easy to see what got him into the world of criminal hacking: the power.

At nine and a half years old he was knocked offline by someone he'd annoyed while hanging out in an AOL chatroom looking for pirated software. "I was amazed that somebody was able to do that," he said.

Intrigued, he soon learned how to do the same to others, a practice called "punting."

Three years later, when his best friend was killed in a winter car accident, Calce said he became a darker, more isolated kid.

"It definitely fuelled me to not really care about what was going on in the real world," he said.

At 15, he had moved from AOL's chat rooms to the EFnet Internet Relay Chat (IRC) network where he learned some very nasty tricks indeed.

The IDG News Service is a Network World affiliate.