SF author and general raconteur John Scalzi writes on his blog about a new collaborative short fiction writing site called Ficlets from AOL.
Relatively easy to browse around, though you have to sign in to access stories marked as "mature" or to submit anything. They allow Open ID sign-ins, so I didn't have to create an AIM or Flickr or Twitter account but used my LiveJournal http address. Not having one of the AOL sponsored accounts means I don't get to use a nifty icon. (sigh) But the whole process takes seconds.
WARNING: This is "all too easy" and could really become violently addictive. I wasn't going to post anything, but decided to write the start to a story, "The Hero Business", which is sort of a mean-spirited riff on an SF novel I read years ago called The Galactic Medal of Honor (1976) by Mack Reynolds. The little editing window is pretty clean and cleverly keeps track of the number of words added and words left as you type. No pressure there.
This looks to be a lot of fun. Not only can you post little story bits, you can add prequels and sequels to your own stories -- or to other people's stories -- under a Creative Commons license. Oh now this sounds like a LOT more fun.
Ficlets is a new site and they are still ironing out some bugs and there are some issues regarding how to find something. Right now there's not too many stories posted. My one story has a URL which ends in 128 -- http://ficlets.com/stories/128 -- which I assume means it is just the 128th story. Cool. Last time I was "on the ground floor" of something new it was way back in 1989-90 or so and the birth of the Young Scientists' Network, where I within the first ten to find out about it.
Must. Go. Grade. Papers. Now.