Is a superfight a fight that makes a lot of money? Is it a fight that the fans most want to see? Is it a little of both?
Unification bouts. Sometimes any of the top 5 facing each other, depends on the fighters really and what's on the line.
John - No Build up bigger than Louis-Schemling II ? I was not around at the time but can believe this was a US - Germany affair with some interested european spectators, ...However Ali Vs Frazier Ist had a truely Global build up adding Communist countries, The Middle East, Africa..thanks to the communications capabilities..and combatants themselves
As a fossil who was ringside for Ali-Frazier I, I can tell you there's never been anything like the anticipation for the Louis-Schmeling return. There wasn't anyone in the world (desert tribesmen, you name it) who wasn't glued to their radio.
I don't think there is a concrete definition. Pac versus Mayweather in 2010/11 would definitely qualify though, due to the combination of factors involved -- both famous, both highly accomplished, both prime or close to it, both possible options for the pound for pound number one spot, the defensive expert against the offensive whirlwind, the guy playing the villain role against the people's champ, the build-up beforehand, etc. I'm trying to think of a recent superfight that actually happened...maybe Mayweather vs Hoya, but I'm not sure about that one. It's easier to name ones from the past. Ali-Frazier and Louis-Schemeling are clear examples. There's also Leonard-Hagler. I have no idea what the build-up to Whitaker-Chavez was like, but that seems like it might be another.