Apparently Mike forgot this shortly thereafter when he stopped doing both. I think "real defense" is employing anything, legal, to avoid getting hit. Upper body movement, blocking, moving your head.
If you consider clinching at every opportunity to be effective defense. I mean, it does temporaily keep you from getting hit, so it is defense. It is not effective over a course of a fight if it is your main tactic.
One of the best from recent years was Mayweather v Marquez. Marquez wasn't as formidable an adversary as the other guys mentioned on this list but Mayweather made him miss nearly 90% of his punches, and put on a clinic with some brilliant slips, rolls, and shoulder rolls.
Nothing, over time people just drift way to other sites for a variety of reasons. I remember prior to joining this site I was on AOL boxing site for a couple of years, and that was also a great site. Meet Iceman John Scully on that site and since we were both on AOL at the time I use to IM him occasionally and chat. I remember he was always working on a book and he occasionally would send me excerpts of it. Here MagnaNasakki was a great poster, he sparred with many heavyweights and he always had a well rounded and balanced view of fighters through the experience he received. I use to PM him and pick his brains about various fighters. Thought the life of a sparring partner would make for an interesting story. Damn hard way to make a living. PhillyPhan69 was another great poster. Hell even Mag1965 the original anti-Duran dude was fun to square off with. (for awhile at least). Probably about another 1/2 dozen or more I could add to this list...