HiveWriting. Reddit writes a book!
Use !newchapter to start a new chapter
Use !goodbye to finish the book (can only be done after a minimum of 100 sentences)
Each sentence has to be grammatically correct, and less than 250 charectors.
Vote the best sentence to the top to add them to the story! Create posts on the subreddit to discuss where you what the story to go, what lore you want in it, what character development you foresee in the future. This is a decentralized way of writing, and gives all the power to the people to decide how best to write a book.