This has happened in the past - for example, Troopers use YouTube to catch Oklahoma City speeder | NewsOK.com . I'm not sure how his case turned out.

I'm not sure why anyone thinks the film can't be used as evidence - I see no reason it couldn't be admitted, especially if it were obtained and subsequently linked to the man's identity (using user account name, IP address, etc.) via subpoena to YouTube (which they will gladly comply with). People have been successfully tried for a wide range of crimes, car-related and otherwise (speeding, street racing, assault, etc.) using evidence from YouTube.

Of course, there are plenty of ways a defense attorney could try to subsequently get the video thrown out (or question its veracity) - for example, arguing that there's no way to prove the exact vehicle, driver, and so on. But with this man's prior convictions and the fact that he's clearly a moron, I doubt that would fly too well.