Quite a few friends of mine have talked about banning their kids (teenagers) from using myspace, flickr, etc. I always try to talk them out of it.

First, do you really want them getting in trouble after they've moved out and the parents have no control, when the parents can't advise and when any legal problems are when they aren't a juvenile any more?

Secondly, I argue that myspace and flickr are the best tools since little brothers and sisters for a parent to watch what their kids are up to. Parents can learn an amazing amount about what their kids are really up to by reading the myspace page and checking all of their friend's pages - that sort of thing (even if the kid keeps their page innocent scanning their friend's pages tells the story). It's like having a hidden microphone...

Of course if the parents aren't willing to spend the time to scan myspace, don't bother keeping track of the kid's friend's names ... flickr & myspace aren't gong to cause a problem but merely document the results of bad parenting.