dana boyd's new book "It's Complicated" is worth reading. It uses real sociological study to balance the public hyperventiation and panic about teenagers and the Internet. It's worth buying, and if you're really short of money there is an authorized free PDF available. Paid sales numbers influence reviewers and the general public, so she'd prefer that people buy it.
One public meme is that "teens don't care about privacy". This is clearly false. Teens care deeply about privacy. But teens define privacy differently than adults. This reflects their social situation, their social inexperience, and their immaturity. Teens define the core of privacy in terms of their relationships with parents, teachers, and similar authority figures. That makes perfect sense in their position. It's not at all what adults are thinking about when they say that "teens don't care about privacy".
There is a lot more to the book as it covers many aspects of teenager socialization and use of the Internet. It's all worth reading.