The Hazing of Kathy Sierra
Yep, some of those boys who didn't want the girls playing in "their" sandbox never managed to grow up. And they've only gotten nastier over the years.
As Lisa mentions, those who know which particular cretins lurk behind the usernames involved need to step up and alert the authorities. Credible threats of sexual assaults, beatings, and murder are illegal for a reason, and the people who make them need to be held accountable.