The Human Project - Connecting people through feelings and stories
Bedtime Stories - The Swiss Army Knife for storytelling
Commaful - Largest multimedia fiction site in the world. A lot of short stories, poetry, and fanfiction.
Tales Untold - Smart stories for smart kids (and smart parents, too).
Kickstarter Spotlight - A page for funded creators to tell their story
Christmas Storybuilder - Generate Christmas themed storylines for kids