In the US at least, those who want various websites to be held liable for abuse of their sites are not being supported in court. Even if the crime is serious.

WSJ:   28 Mar 2009:   "In February 2007, MySpace won an important court victory when a Texax court dismissed a lawsuit by the mother of a 14-year old girl who was sexually assaulted by a 19-year-old she met on MySpace.   The widely publicized lawsuit charged MySpace with negligence and fraud for failing to take reasonable safety measures to keep young children off its site" .

In another case which went to the Supreme Court, Justice Stevens wrote for the majority on the issue of anonymity--obviously pre-Facebook-- in a 1995 opinion:   "...The right to remain anonymous may be abused when it shields fraudulent conduct. But political speech by its nature will sometimes have unpalatable consequences, and, in general, our society accords greater weight to the value of free speech than to the dangers of its misuse."

But the same article also stated that Facebook now requires people to use real identities--(and it traces its recent explosive growth to this policy.)

Obviously this is not the case--the "real identities" people have to use are not in fact always real identities of the people submitting them . The crucial question is clearly: how does Facebook ensure that the identities are actually real?--since whatever method Facebook is employing to assure this is not working.