Online dating is intimidating enough without added concerns about physical violence. Two years ago a woman in Los Angeles was attacked by a man she met through an online dating site who'd previously been convicted for sexual assualt. A serial rapist in Philadelphia picked targets from a dating site. There were several Craigslist killers.

Measures being introduced nationwide seek to make dating sites more transparent, and safe.

Robot Prostitutes, the Future of Sex Tourism

Connecticut, New York, Florida, Texas, and New Jersey are among states that already have laws requiring dating sites to post safety notices. The Illinois State Senate recently passed legislation requiring dating sites to tell their members whether they perform background checks using government databases. Any site in violation gets fined $50,000.

DNEWS VIDEO: Science and Technology Help Find True Love

As a result of the lawsuit brought by the L.A. woman who was assaulted, started screening for sex offenders. Match was also one of three companies, along with eHarmony and Spark Networks, that announced this spring they would introduce new safeguards against sexual predators, scammers, and identity thieves. That includes weeding out fake profiles.

The algorithm-driven site OKCupid doesn't trumpet background checks but does have a legal disclaimer with safety information and instructions on how to report harassment and other problems. Particularly paranoid daters should do extensive online research and even call college registrar offices, advises author Maria Coder in her book "InvestiDate." Background search services and tools like, ValiMate, and Date Check have sprung up as well.

Kissenger: Virtual Lips for Long-Distance Lovers

This week a woman claimed that had tried to pair her with James Holmes, the man accused of killing 12 people at a movie theater in Aurora, Colorado. She apparently took screenshots and notified the site. I couldn't determine whether this was true, but a background check wouldn't have helped much in that scenario since he'd previously only had a traffic summons.

When filters and online searches aren't enough, a good gut instinct can make all the difference. Any profile with the headline "Will You visit me in prison?" is kind of a tip-off.

Photo Credit: Don Hankins