LOS ANGELES, May 23 (Xinhuanet) -- To protect their children, parents must be more vigilant in keeping tabs on teenagers' activities online, child safety advocates said in a study released Monday.

    In a latest survey, slightly more than half of US parents say they don't have monitoring software on household computers that teenagers use, or don't know whether their computers have such software.

    The survey was conducted by US National Center for Missing and Exploited Children and broadband service provider Cox Communications.

    Similarly, 42 percent said they don't review what their teenagers are reading or writing in chat rooms or via Instant Messenger software, according to a CNEWS report.

    That compares with nearly half of the parents surveyed, who said they monitor their children's online activity daily or weekly.

    Almost three in 10 respondents were unaware whether their children chat with strangers online.

    Part of the problem for parents could be where computers are located. The survey reported that 30 percent allow teenagers to use computers in bedrooms, home offices or other private areas. Parents said they were more attentive when the teens and PCs mix in more public areas.

    The biggest hurdle for the adults is to keep up with teen "jargon" on the Internet. That means common chatting terms like LOL(laughing out loud), BRB (be right back), and more to the point, lingo like POS (parent over shoulder) or P911 (parent alert) used to indicate that parents are watching.

    Social researchers and child protect groups said children may easily become victims if they are seduced by criminals in chat rooms. In fact, many media reports have disclosed that children encountered strangers on Internet before they were missing.

    "We all know that the Internet is a fantastic tool for children to use and learn from," children's advocate and famous TV talk show host John Walsh said in a statement. "However, parents need to be engaged with their children's online habits to prevent the unthinkable from happening within their own home."

    Walsh, best known as the host of TV show "America's Most Wanted," plans to host a program on Internet safety, which will be aired by Cox channels starting in June. Enditem