YouTube is one of the most popular Web sites. But it isn’t the most kid-friendly site. It takes about two seconds to find videos meant for adults. I’m not talking about porn.

That’s explicitly forbidden on YouTube, though it pops up occasionally. YouTube gets so many video submissions that it’s hard to monitor everything.

There are videos full of obscenities, violence, drug references and mature themes. Some of these videos are age restricted. That means your kids must have a YouTube account to view them. Getting an account requires entering their ages. But children can lie to get around this. Plus, many videos that should be restricted simply are not.

YouTube has also begun posting full-length movies. Some are rated R. And again, not all of them are age restricted.

Letting them watch

Beyond the unreliable account system, YouTube has few parental controls. Your best bet is to surf with them. You’ll have control over what videos they watch. Or you can choose from a number of more kid-friendly video sites.

You can also help clean up YouTube. It relies heavily on user feedback to monitor videos. Below any video, you’ll see a Flag button. You can use this to report videos that break YouTube’s Community Guidelines. The staff reviews flagged videos. And they will remove objectionable content.