In discussing online communication tools, it’s hard not to include a concept map. We use them so much in education to help students to brainstorm and think through their ideas, so it seems only natural to include one on our list.
The concept map that I like the best is MindMapFree. MindMapFree is, as it states, free. It is also completely online with no login required (or even offered).
This application is easy enough for younger students to grasp quickly and robust enough for older students to add all of the elements they need.
Even though no login capability is provided, users have the option of saving their map into Dropbox, into your browser’s local storage, or downloading the file to your desktop in a proprietary file format. The file can easily be uploaded again so that students can continue from where they left off.