On Thursday, the U.S. Attorney for the Central District of California announced that Lori Drew, now 49 years old, was indicted on conspiracy and hacking charges. The indictment charges Drew, a resident of O'Fallon, Missouri, with three counts of unauthorized access by violation of MySpace's terms of service and one count of conspiracy.

... ?

Where hacking = Computer Fraud and Abuse Act.

So, the DA's logic is that that by violating MySpace's TOS, Drew was no longer an authorized user of MySpace's systems and thus by continuing to use MySpace she committed unauthorized access.

There is a good write up over at The Volokh Conspiracy by Orin Kerr and I highly suggest you read it.

A few choice quotes from Security Focus's coverage:

Yet, legal experts argue that charging a person for violating computer-crime statutes because they broke the terms-of-service agreement of an online site could lead to the ability to charge nearly anyone with computer crime. Using residential broadband for business purposes? A violation of the terms of service and, thus, potentially a crime. Checking sports sites while at work? A violation of corporate policy and, thus, potentially a crime.

and

"There is nothing in the indictment that differentiates between what is a serious violation of the terms of service and a trivial violation of the terms of service," Morris told SecurityFocus. "I would bet that the majority of U.S. Internet users have committed a federal crime, if the charges in this indictment are upheld."

and my personal favorite

"Violating a website's 'TOS' is carte blanche to an imaginative prosecutor," Greenfield said. "We are all felons if this flies."

MySpace Suicide Indictment: or TOS violation = crime