Hi there.
I posted about this a few years back when it was still a prototype. Now I've finished work on version 1 of Fablelane, which is a modern collaborative writing community that can easily get you a lot of inspiration.
It's very fast-paced, and can be a good supplement if you're stuck writing and need some inspiration. You can use the site anonymously, but will of course receive benefits by signing up. We won't post stuff on your behalf or send you spam.
I had a dialog on Skype with the creator of Infinite Story a year ago. We talked about collaboration and maybe interlinking the two sites, but I have not heard from him since.
Is he still active?
Oh, and leave me some feedback on what you think about Fablelane please!