MySpace has high hopes for the technology, which is being called Sentinel Safe.

"The creation of the first-of-a-kind real-time searchable database technology is a significant step to keep our members as safe as possible," MySpace's Nigam said in a statement announcing the initiative. MySpace hired Nigam in April from Microsoft, where he acted as a cybercrime investigator, to help the company secure its service.

MySpace will pair its use of the database with a security team available around the clock to deal with any potential database matches, Nigam said. The deal with Sentinel aims to head off convicted sex offenders from using the service for any reason.

The MySpace initiative will likely reignite a debate over sex offender registries. Citizen rights groups, such as the American Civil Liberties Union (ACLU) have criticized the registries as error-prone and overly inclusive of even minor crimes. A spokesperson for the ACLU on the issue could not immediately be reached.

Moreover, MySpace may have to defend its assessment that anyone convicted of a sex crime should not be allowed on its service. In a 2005 op-ed letter to the CrimProfBlog, Margaret Colgate Love, a twenty-year veteran of the U.S. Department of Justice, criticized the policy of posting such lists online, arguing that they lead to vigilantism.

"I am sure there are sex offenders living in the community who need to be surveilled, and probably some who really should be locked up," the letter stated. "But the clear suggestion that all 500,000 registered sex offenders in the United States are 'predators' is one of the most irresponsible I've seen come out of the Justice Department, ever."

In April, a 24-year-old Maine man was killed by a vigilante, who subsequently killed himself, when his name was taken from that state's list of sexual predators. The victim had been convicted of having sex with a minor when he was 19 years old.

MySpace said the technology will be ready to be deployed in 30 days.