Basically how it works is that everyone signs up with a request with prompts/pairings they want someone to write for them. Then when the sign-ups close, I assign SPEWers to write stories for other SPEWers, based on matching up what you will be willing to write with someone else's request. So it might look like this:
Jess will write for Mere
Mere will write for Jennifer
Jennifer will write for Soraya
Soraya will write for Jess
So basically you write a story for someone, and someone else will write one for you. But the only thing you know is who your story is for, and you don't find out who wrote one for you until after all the fics have been posted on our community,
spewswap.
And - I really have to stress this - please do not post the story anywhere else until after I've revealed the authors at the end. If you post it to the archives or have parts of it floating around the forum, then it ruins all the fun of the surprise stories at the end of the swap. The only people who should see it are you, your beta, and me when you send it in.