In terms of the site itself, I would want anda to be able to change your username. Some sites only allow anda to do it every 6 months after anda last changed it, so even if fanpop would just do that, I'd be a lot happier with the site. And if there was an app, that'd be awesome!
The only thing I'd like to really see on fanpop is lebih hadiah and lebih opportunities for anda to get to talk with the admins of the site, like Dave and Cliff.