"Registered sex offenders will have to start providing their e-mail addresses to a national database available to social networking sites, under the misleadingly titled "Keeping the Internet Devoid of Sexual Predators Act of 2008" — a bill authored by Senator John McCain and signed by President Bush on Monday.
The idea behind the law (.pdf) is that a social networking site can query the database to keep registered sex offenders from signing up, and thus prevent them from preying on underage users. Needless to say, the law does nothing to stop first-time predators. But it's doubtful that even recidivists will be affected. Pedophiles looking to victimize children — a felony worth years, even decades, in prison — won't be afraid to violate this new law by using an unregistered Gmail address. And now law enforcement will have to struggle to discern whether an offender is using a disposable webmail account to commit new crimes, or just to shunt the blacklist and network with their adult friends and family."http://blog.wired.com/27bstroke6/2008/10/mccains-sex-off.html
(edit) making laws that are not enforceable or are easily bypassed are a waste of time and money just like regulations that can be followed or enforced. Once we all have a firstname.lastname@example.org email address AND we all had to use it this might be a law worthy of some effort put into it.