Do আপনি think most of the twilight and harry potter সংগঠন here are dying ???

I don't think so. I don't know any thing about the Harry Potter clubs, but the Twilight সংগঠন seem fine.
They're not as active as they were a couple years ago, but they are very far from "dying".

(It would be wise to actually look at Twilight সংগঠন before concluding that they are all dying because "Twilight is just a phase")

Twilight yes but harry potter? Never Ever will harry potter অনুরাগী সংগঠন 'die' but twilight is just a come and go phase

They both seem pretty full of activity.

I can only speak for HP, and we still live and kicking so to say. ;D
and when আপনি say here, do আপনি mean fanpop?
because when it comes to HP fandom we mostly play in LJ, AO3, and tumblr...
in tumblr we are starting a new role play game. and this november there are new fanfic festival going on.
well, in ফ্যানপপ the goings on are definitely less compared to when the movie still going on. since not much we can do here other than মতামত and answering প্রশ্ন that has been repeatedly asked.