On February 1, 2004 the New England Patriots beat the Carolina Panthers to win the Super Bowl.
Because, we all saw Janet Jackson's boob at halftime. She has an interesting looking piece of jewelry on her nipple. Thanks, Justin Timberlake.
It was the most TiVoed piece of television, ever. About 143 million people saw it live. Then, a ton of people re-watched it...and re-watched it because of the internet. The inventor of YouTube says its one of the reasons that the video site was created.
The incident also led to pretty much the end of Janet Jackson's career, but served as a launching pad for Justin Timberlake (take that however you wish).
There was a lot of fallout with the FCC. No comment.