I am constantly amazed at how people post stuff on the internet forgetting that others have access to what they post... I like to tell my students jokingly (although it is not entirely a joke) that "facebook makes you dumb." Here is another example: In a recent case the South Carolina Supreme Court disbarred an attorney who did not reply to a number of alleged ethics violations, among them a charge that he maintained a webpage with the name of his law firm on MySpace.com that contained profanity and nudity along statements that suggested he had been using drugs during the week prior to posting the comment.
Listen people: if you post something on the internet, others will read it. It can and will be used against you.