Fanfiction.net - The most popular fan fiction website in the world according to Wikipedia
Goodreads - See what your friends are reading.
Belletristica - Your online writing platform. Share your stories and poetry with the world and become part of our community!
Readernaut - We are a small community of readers, sharing our adventures and supporting each other as we persue a life of learning.
Wattpad - Wattpad is now the worlds most popular ebook community where readers and writers discover, share...
aNobii - aNobii is a social network for listing books, sharing insights, and meeting people.