I spent some time looking at a bunch of the tools and ended up playing with Mindomo. I assigned (among other books) Charles Dickens’s Hard Times for summer reading, so I made a mind map of part of Chapter 5 while I was doing my own reading. Making the map was fun and easy. I haven’t explored enough to see whether you and students can all collaborate on a mind map together in real time, but I think that Mindomo would be a fun thing to put on the board during a class discussion and make a mindmap of our discussion as we go – so as students bring up topics and ideas, we can put them on the mind map, and by the end of class we’ll have a visual diagram of our entire discussion. They could perhaps use the mind map as a study tool – and if we have a course Wiki, I could post the discussion on the Wiki. Absent students could see what we discussed that day, and students could use the map later, as I mentioned, to study or use for ideas in writing their essays. Students could also use the program to make their own mindmaps as they are reading – we could explore how to post these to a group page so students can see one another’s ideas.
Here’s a link to the map I made. I think Mindomo could possibly be Bang more than just Bling.