But a California lawmaker says the background checks can be far more serious. The lawmaker, Assemblywoman Fiona Ma, the San Francisco Democrat who is the majority whip, introduced a bill last week to create an online database of men and women convicted of domestic violence in California.
Other states like Florida have databases used by law enforcement officials. Her proposal, Ms. Ma said, would be the first available to the public.
"If you're online, Googling and looking for information on someone you met in a bar or on MySpace, this would provide a tool for people to go and look to see if someone who is suspicious and a little creepy has a history of violence," Ms. Ma said.
The database would log the names of domestic violence offenders convicted of a felony or two misdemeanors, dates of birth, locations of convictions and other information. Unlike public registers of sex offenders, the database would not list addresses. It would, however, indicate how to obtain a restraining order.
"The site gives people knowledge," said Jim Hammer, a former San Francisco prosecutor who worked with Ms. Ma on the bill. "To enable people to get restraining orders is giving them the power to do something about it."
Mr. Hammer took the database idea to Ms. Ma last year. It came to him in the late '90s, he said, after he prosecuted Ronnie Earl Seymour in the killing of Nadga Schexnayder and her mother during a domestic dispute in 1995.
Ms. Schexnayder's parents had suspicions about Mr. Seymour, with whom she had a child, but they did not have the tools to check his background, Mr. Hammer said. Mr. Seymour had three felony convictions for attacks on former girlfriends when he killed the two women. He was sentenced to life in prison.
"They didn't have the means to hire a private investigator to go to courthouses and pull documents," Mr. Hammer said. "They had feelings, but no evidence."
The bill would impose higher fines on domestic violence offenders to pay for the Web site, which the attorney general's office would run. Ms. Ma said that she was optimistic about its prospects for passage, but that it was too early to gauge support in the Legislature.
Ms. Ma said the measure singled out domestic violence offenses because national statistics indicated that those crimes had a high rate of recidivism.
"Domestic violence is a cycle, and it's hard to break," she said. "But knowledge is power, and this is public information that's already out there. This site would make it easily accessible."