Terms of service online are routinely breached, sometimes unwittingly, sometimes deliberately. Violations include checking work e-mail from home (most residential broadband services forbid business uses) and submitting fake personal information when posting comments online. If a terms-of-service violation were all it took to bring federal charges, overly zealous prosecutors would be in a position to indict just about anyone who used the Internet.
Megan's story is tragic, and it's easy to see why prosecutors might want to stretch federal law to fill the gap evidently left by the Missouri penal code. (In her defense, Drew has told authorities that she was simply trying to find out what rumors Megan might have been spreading about her daughter online, and that she had no direct involvement in the messages. One of the girls who participated in the alleged conspiracy has admitted to sending the last message to Megan, which said in part that "the world would be a better place without you in it.") Nevertheless, the anti-hacking statute is a poor choice, and Los Angeles is the wrong venue.
State laws against cyber-bullying and other forms of harassment are designed to draw the line that separates death threats, stalking and other injurious behavior from deceptive but legal speech. It's an important distinction that the federal statute ignores, and it shouldn't be lost in the outrage over Megan's death.