Is it クラブ または Spots?

i think the reason it was changed was that もっと見る people would 検索 for "fan club" on e.g. google- they are もっと見る likely to find ファンポップ this way. あなた might 検索 for "how i met your mother ファン club" on a 検索 engine (if あなた dont know fanpop) and no one would 検索 for"how i met your mother ファン spot". also people immediately understand how a ファン club works..rather than having to wonder what on earth a ファン spot is.
im thinking the もっと見る users 登録する the もっと見る "club" will become common.

right now there are still plenty of users who say "spot" because they are used to it and because it seems very ファンポップ specific. if someone on ファンポップ says "i saw it in the club" they could also mean a different ファン club...or a golf club for that matter. so when using "spot" everybody gets what あなた mean immediately. but like i said..im guessing that will change. im pretty sure the faqs and such still have the term "spot" used.
quite confusing the whole matter ;)

Spots and クラブ are the same thing. The F4 just changed the name to make it less confusing for new users, since "spot" doesn't sound as much like a fan-site. However, the term "spot" is still commonly used.