Not yet, but according to this bài viết bạn will be able to soon:
link "-User name changing. Yes, apparently, a few people want this for some unknown reason. What the heck is wrong with bonerAlert89 ? vàng will keep this from going too crazy as it's hard enough to keep up with your 1,000 những người hâm mộ and all their new names each week."
Basically, they're soon adding a feature where bạn can earn "gold" for doing certain things on Fanpop, and one of the many things bạn can spend it on is changing your username. The fact that bạn will have to spend vàng on it will mean that - hopefully - users won't just be mindlessly changing their tên người dùng every few minutes. They will have to think carefully about it first.
