Well, I play WOW (World od Warcraft for you non-gamers) and they are called guilds, not clans.
They are actually really vital if you are really into the game. It allows you to play with the same bunch of people all the time. Most of these game have adventures that require 15-40 people, and you certainly don\'t want to play with random people so 1) they keep getting you killed because they don\'t know what they are doing and 2) They steal the uber items right under you when the Boss is dead.
Some of these games require fairly complex coordination, and hence, if you want to play high level content, you have to be in a successful guild.
On CMON, not sure what that would do besides mark you as a Black Primer cult, White Primer cult, NMM clan or Metallic clan, just to identify your preference
