I'm involved in a new project with the Kellogg Action Lab, and one of the things that was needed right out of the chute was a way for a few people to share ideas between face-to-face meetings. Only two of us are working on this project now, but more are expected soon. Obviously we can work on documents together, particularly if we use Open Office (which I swear by).
But we really just need a place to post ideas and clean up/edit others' thoughts in a common format.
Enter a wiki. Thanks to my son Ben for reminding me that when he and his business partner were in the early stages of their startup, they used this great tool. So, I went out and did about a 10 minute search and check and choose ClearWiki. It's easy to set up, easy to use, includes WSIWYG editing, and is free for up to ten users. Works for us. One feature I really like is the "Move" feature-as I figure out the best hierarchy for this emerging project, I can instantly move one page to be under another topic thread.
But don't just take my word for it. Lots of other wiki providers are out there. Here's a list from (appropriately) Wikipedia.
Here's a set of nonprofit wiki stories from TechSoup. Take a look at the wide variety of uses, and remember this tool. It works.