education on data protection is very important these days. As the example with your student shows, they are not prepared. I teach my kids these things wherever I can. They are allowed to use social networks, but must keep privacy settings high, and learn not to post anything private or important. But still, these networks are great for helping maintain a lively social life with many people at once - I have learned to understand the benefits of it from my kids, actually. Now that I'm using FB too, I think it's a great thing, but it's true you have to be careful. Not only because of the privacy settings, but also a healthy mistrust to the service provider is important. If you think twice about which messages you send, what you write in chats, and of course posts, and what you choose to "like", is all not privat necessarily.
With these things in mind, though, you can safely enjoy the benefits that remain.
Regards,
Frank