Updated

New laws passed in 25 states are making it easier for social networking giants Facebook and MySpace to purge their membership lists of convicted rapists, gropers and child molesters.

More than 3,500 offenders registered in New York have been kicked off the two popular Web sites in the months since the state implemented a law requiring sex crime convicts to register their e-mail addresses, as well as their dwellings, attorney general Andrew Cuomo announced Tuesday.

Both MySpace and Facebook have long had policies banning sex offenders, and have routinely used state registries in the past to block tens of thousands of convicts from joining.

But the task of identifying convicts among millions of users has been both tricky and labor intensive, and the companies said Tuesday that New York's new law and others like it are streamlining the process.

"Our program was very successful, but we wanted to add an extra layer of protection," said Hemanshu Nigam, chief security officer of MySpace and its parent company, News Corp.

Over the past two years, half the states have passed sex offender e-mail registration laws similar to the one now in place in New York.

Congress has also passed a law creating a national sex-offender e-mail registry, although it has not yet been implemented. The details of the system are still being developed by the U.S. Justice Department.

The registries are intended to solve a series of obstacles to efforts by social networking sites to keep offenders from enrolling.

Previously, not every state has kept its data on offenders — usually a list of names and physical addresses — in a form that can be mined easily and automatically by computer.

"In some states, when we asked for their list of offenders, they'd fax it to us," said Facebook spokesman Barry Schnitt.

Verifying that a person is actually a sex offender before they are kicked off is also a chore. MySpace has a team of investigators working 24-hours a day, 7 days a week, making sure that people whose names show up on offender lists are who the company thinks they are.

That verification process is easier if the sites start with an e-mail address, rather than a brick-and-mortar one, Nigam said.

In New York, some 25,000 sex offenders are now required to register their e-mail addresses, as well as any instant-messaging handles or other Internet screen names. To date, 8,100 have supplied that information.

New York began making the registration database available to social networking sites this year. So far, Facebook and MySpace have been the only two services to access the data. Since the info became available, Facebook has blocked 2,782 accounts. MySpace has terminated 1,796. Some offenders had accounts on both sites.

Cuomo called on similar Web sites to participate in the program, saying "it's time for all social networking sites to do their part to keep others from being senselessly victimized."

State investigators are now going through the list of people banned from the site to see whether any had been ordered to stay off the Internet as a condition of their probation or parole. If so, they could face criminal charges.

MySpace reported in February that, even before the implementation of e-mail registry laws, its internal measures had already succeeded in identifying and blocking some 90,000 convicted sex offenders nationwide.