Actually it was directly related to message boards, though I don't believe this article has all of its facts straight, the details of how he actually got taken into custody up here don't matter. The article also doesn't talk about how the cop found out who Gkae was in the first place, which was also because of kids talking on the internet:
Officer Randy Campbell of the California Highway Patrol had tried the usual means of catching a criminal before turning to the Net. The breakthrough came when Campbell discovered that many taggers set up Web sites to display pictures of their graffiti. The Net helped Campbell figure out where to find **********. Through a newsgroup for graffiti artists, Campbell learned that ********** had moved on to Seattle, and he notified the police there. Soon the Seattle cops started noticing G.K.A.E.-signed scrawlings. A lucky beat officer in his squad car caught ********** red-handed at a wall, spray paint in hand, signing his moniker to his artwork on a wooden fence at a construction site. Campbell filed for extradition and handed over the downloaded evidence to prosecutors. *********** was convicted of felony vandalism.
So basically, watch what you say on here about other writers or yourself. It can and will help the police out.