A success Wikipedia has thus far been, though issues there are still. Observations, on these issues I will make.
1) Wikipedia is a collaborative website that tries to be an encyclopedia. Wikipedia's got a funny name: It was named by the founders after the "technology" it was based on, rather than the philosophy it was based on - openness, egalitarianism, honest and honorable conduct, etc.
2) Thus the name "wiki" itself is misapplied to en.w.pedia "Wiki" is a technological concept. "Wikipedia" is an egalitarian one. Though people have for years tried to turn "wiki" into a larger, more philosophical term, it just doesn't want to go there - wiki ultimately doesn't mean anything more than "quick." We want "Wikipedia" to be more than just a quickie resource.
3) Wiki facilitates easy editing, but then not everything we do is editing. In fact the main thing Wikipedia does is just exist - existing in a digital form at a free/open-access online database for ease of reading/viewing. Wiki makes lots of things easy - some of which are conducive to making an encyclopedia. The wiki made vandalism easy too, but we learned that collaboration itself could deal with that.
( 3b) (It's the infrastructure/databases/operatingsystems/browsers themselves that facilitate this ease - not just "wiki." Still, we don't call ourselves the "inter...pedia" or the "web..pedia" for a reason: Those domain names were already taken. ;-) )
-Stevertigo