I recently heard a politician having to deal with something he posted three years ago on a forum (that was actually transfered, unbeknownst to him, to a VERY controversial website). He said his postings were in good fun and that they were taken out of the context of what was being said in the forum, yet since his name was on those postings and they made it to another site, he was still accountable for what he said. Scary.
I am careful about Facebook because I am a school teacher and I have my assistant principal as my friend, so I don't say or respond to anything controversial on there. My husband is VERY opinionated and I have had to encourage him more than once to remove postings he has made because they could really get him in trouble.