for those who use facebook, the following website http://youropenbook.org/ is trying to get facebook to change its default "privacy" policy (which, as the site demonstrates, is a policy of zero privacy). Type in any word or phrase and see the list of people whose facebook status includes that. It might be a good exercise for students to engage in as well, to test their current settings.
I did some random searches by the way, one of which was on plagiarism, and here is my favorite status on the subject from someone in Reno, NV: "So I found a book full of Greek mythology from thousands of years ago at the store... and it says (c) 2007 at the beginning. Seems to me that copyrighting someone else's stories, however old, is still plagiarism."