For several years now, I've used Steve Yost's QuickTopic to coordinate discusssions and group activities. Setting up a discusssion is simplicity itself: it takes a minute or two. Instructions are in plain English. It's a well-honed application -- intuitive to use and unburdened with clutter. Did I mention that it's also free?
QuickTopic Pro was released a couple of days ago. For $49/year, the Pro version lets you customize the look & feel, and also upload pictures. That $49 lets me customize the dozen QuickTopic discusssions I'm running.
Take a look at my scribble space to see what I'm talking about.
The free version is still available. This is an exemplary marketing strategy: Try it; you'll like it.
Imagine using QuickTopic as an informal learning tool:
Help me think up more applications.