What are some alternatives?
Fanfiction.net - The most popular fan fiction website in the world according to Wikipedia
Storyboard That - Storyboard That is the world's best online storyboard creator.
Cowbird - Cowbird is a simple tool for telling stories, and a public library of human experience.
Penana - Read the best stories from our aspiring writers! Come in to interact with writers and other fans!
Little Bird Tales - Little Bird Tales: Capture the Voice of Childhood.
oStorybook - oStorybook : a free Open Source novel writing program for creative writers