Police say MC Hammer's cousin sexually assaulted a woman in a San Francisco-area hotel. Twitter will be in the lead of every story about this, and not just because that's where the accuser and accused met.
Of course, none of these networking sites are inherently evil, but as they grow they encompass a wider array of human behavior, including, eventually, the worst forms. It's arguably newsworthy when the sites' users cross various depraved landmarks. A social network's criminal record grows less sensational as it becomes more common, reflecting the population at large.
The Twitter/rape story is extra newsworthy due to the connection to a famous rapper, and the fact that the accused is also a regular on MC Hammer's reality show, Hammertime, where he's known as "Lyin' Marv." Lyin' Marv is 100% culpable here, if he indeed found guilty in the attack. That said, it's worth noting that the dumb move in this situation wasn't so much using Twitter as it was scheduling a rendezvous, in a hotel, with a guy you met on the internet, with "lying" right in his name.