who he is. i have never even watched one of his fights, but he would be covered on SportsCenter and other media all the time. He would appear with numerous other celebrities in ads, talk shows, high profile events.
He has been arrested a few times with crazy media coverage. He had a long string of commercials that played during every sporting event. He has appeared in movies, reality TV...
He has been unavoidable for anyone that watches sports in the past decade.
And even for those that don't watch sports. My wife has never seen a UFC or boxing match of any kind, nor watched sportscenter. She could no more tell the difference between a quarterback and a short stop, but she knows who he is.