Internet Safety/Common Sense?

I recently listened to CBC radio report about a 16 year old tape which had surfaced as political parties switched offices. This tape was a video tape of several key people, including our now Premier, talking in front of a video camera. The remarks recorded included anti-gay, anti-labour, and rude comments about other politicians. Currently we are trying to explain to our students that when they put up pictures or video or a blog on the Internet that their views are there for all to see. We warn them about posting things which may reflect badly on them in the future and on those things which are simply inappropriate. In light of the comments recorded on this tape which is now posted on You Tube and CBC are we actually having any success? Does anyone use common sense anymore or did they ever?