Teens are teens for a reason. It's because they aren't yet adults. That's why we have to keep a close watch over them.
A lot of teens have no idea that what they're posting may have ramifications later on in life. If it's on the Internet for one second, it's on the Internet forever.
This is what teens do. They act out and pretend to be cool. It's not easy for them in real life, but online they just have to change the background of their Web site to be cool.