There's a myth that children spend all of their time on the Web visiting the and sites and other destinations designed specifically for kids. In reality, the single most popular site for children is .

does a great job keeping explicit videos off of YouTube. The vast majority of videos would be rated G if they were theatrical films. But there's plenty of R-rated content, as well. The filtering rules for YouTube adhere to technical guidelines, as in: You can't show this body part and you can't show that body part. But anything can be said (there are no filters on language). And anything can be suggested, implied or described.

YouTube is also used as a lure by purveyors of what most parents would consider objectionable material. YouTube hosts, for example, thousands of clips from porn movies, with technically objectionable content cut or blocked, but with easy links and information about how to find the rest elsewhere. These videos serve the same purpose as movie trailers. And while they meet 's YouTube guidelines, they advertise content that doesn't.

I don't mean to overstate these threats. Statistically, the risk of any given child of being targeted by online predators, bullies or irresponsible pornographers is probably low.

Unfortunately, the chance that they will be affected by some kind of Internet-facilitated addiction is very high.