You guys also have to keep in mind that he grew up from a very young age in the lime light. He touched a looot of people, as Deathshand said.. If you want to talk about the most popular international superstars in history, Mike has to be in the discussion.
Since he's been popular for so long, people watched him grow up, and get more of that feeling of actually knowing him. Even though in his last years he had changed a lot, it didn't matter because people loved him unconditionaly.
I could understand how people in their teens or lower wouldn't have that same connection though. R.I.P Micheal.