Back in the ancient days before real mainstream gaming, there was a dearth of good titles to play. It was a cultural phenomenon at that time to extend gameplay for the few good games that existed by creating emergent challenges for themselves. This is where the concept for the speedrun came about, although the speedrun changed dramatically after that time into something very unique. Still, gamers have been artificially injecting challenge into games ever since the '80s.
A game like Champions Online has a fair number of factors, including a smaller endgame and a lower overall difficulty level, that make it ripe for injecting some artificial challenge.