Tumblr Books
From Jenna's NYT story about blog books: "But the latest frenzy is over books that take the lazy, Tom Sawyer approach to authorship. The creators come up with a goofy or witty idea, put it up on a simple platform like Twitter and Tumblr, and wait for contributors to provide all of the content. The authors put their energy into publicizing the sites and compiling the best material."