What are some alternatives?
Storybird - Visual storytelling community
My Storybook - Make children's storybooks online for free.
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.
Archive of Our Own - An Archive of Our Own, a project of the Organization for Transformative Works
oStorybook - oStorybook : a free Open Source novel writing program for creative writers