How about social networks?

You need to hear this sermon. It was preached in 2006, mainly about Myspace. While Myspace is not nearly as popular as it was then, most of the young people and adults also, have moved to Facebook. The principles apply to social networking. Young folks, Wake Up!!!   Parents Wake up!!! Folks, once something is on the Internet, you cannot get it off. Don't ever post anything that you would not want your pastor, your parents, your teachers or your employer to see.

Bear in mind that Facebook frequently changes its privacy policies making more of your private info public....until you find out about it and "opt out".  Many times they have "unintentionally" sold private data and their response?  "Oops."   The founder of Facebook says "privacy no longer exists."