What Is The Meaning Of Club In Common? And Why Does I Only Can See It In Other ファン Page?

It means..that あなた and other ファンポップ users like the same things so there in the club too, and あなた only see it on other users page not on you're page cuz it tells あなた what クラブ あなた have the same as the user whom you're visiting their profile..if あなた don't get it just wait for もっと見る explanations

it'd called CLUBS IN COMMON what do why think it means?

Like someone else said, it shows the クラブ that other people have joined that あなた have also joined.

It's a way of seeing if あなた have common interests with another user. ^^