For the past four years I’ve been exploring ways to use wiki software for collaborative fiction writing. During that time I have seen many non-wiki websites that are devoted to collaborative writing. Examples: Pan Historia, Orion’s Arm and We Book.
However, there is nothing magic about wiki software. Knol is an example of an online platform that supports collaboration with a non-wiki use interface. I think many authors like the idea of being able to control who they will collaborate with, so using a Knol-like platform for writing appeals to some folks. I recently registered at the Book Oven, a new and developing non-wiki website that allows for collaborative writing. It will be interesting to see if that little community can get off the ground.
Similar website: Fast Pencil.