Of course you have. Everybody has.

But now, through the marvels of modern technology, your words stay with you forever.

I just hope that one day this becomes a universal revelation, and we as a society become much more forgiving. The combination of harsh judgement, poor decisions being easy to make, and a public permanent record of anything you say on the internet can have potentially life ruining consequences, and it's easy to find plenty of examples today. In the past, only people who were in positions that would be in public scrutiny (politicians, CEOs, PR people, etc) really had to watch what they said all the time. Now that we have the internet, which doesn't really forget, it's easy for past mistakes to come back to haunt you. I just hope society becomes more lenient about foolish mistakes...