How do Du know if a club is "pending" oder "official" and does it have any effects when a club becomes "official"?

If a club is still pending, then it'll be listed in the "Pending clubs" section that's linked to the Home page.

If it's a full club though, if Du go to a certain category of clubs, for example, the "Celebrities" category where it lists all the Clubs in that category, only full Clubs are listed there, so pending Clubs won't be.

I think a club has to get at least several hundred members to not be pending anymore, the fewest number of Fans I've ever seen for a full club was two hundred-something.

i cant actually think of anything that changes once its a full club and i think the f4 can actually promote spots..but i cant remember where i read that, so i might have been imagining things.
the process i am guessing is some sort of secret formula like the medal formula..something along the lines of X*links+activity*Y*magic fanpop*elves doing their work-cookies+images