True.com

True offers criminal background checks, as well as marital
background checks, and the company says it will prosecute
anyone who commits fraud on their Web site. Brooks calls
these fraudulent abusers "spammers, scammers and obscene
pests."thanks to online dating services such as True.com,
ensuring user safety is becoming a top priority for many
matchmaking companies.

True is even pushing legislation to add background checks
to all dating services, or to at least add a note that
says they don't offer background checks, says Brooks.

"Women need to know that when they go on a date, they're
not talking to a criminal or someone who is married," says
Brooks. "The Internet dating industry is doing a far
better job of getting rid of people who abuse the system
because their brands are attached to the people on their
sites. This is partly because of what True has done with
safety."

source:

I have to say, this is a fabulous idea. I always ask
questions and try to get information on a prospective
mate. Kind of goes back to the, "if it sounds too good
to be true, it probably is"