ポッターモア club as in the spot on Fanpop? That's up and running.
But if あなた meant ポッターモア the site... Well, no one really knows. At first they 発言しました end of October, but then the developers realized it had way too many bugs and beta testing needed to be extended. On ポッターモア Insider they stated that the site will not be opening to new users in the immediate future, but please know that we will open registration as soon as we can. Take that however あなた want.
