Free mind-mapping software written in Java.
A forked version Freeplane exists.
Ranked in these QuestionsQuestion Ranking
Pro Free and open source
Pro Intuitive UI with drag and drop support
For the most part, navigating the editor is pretty intuitive - moving around is done by clicking and dragging the background, clicking on nodes will expand/collapse them, dragging and dropping in files will add them, etc. It also offers shortcuts for power users. For example, ctrl + up/down will rearrange ideas up/down, alt +up/down will zoom in/out, etc.
Pro Lots of export options, including html with folding
Freemind offers many choices when exporting. It allows exporting the project as Java Applet, Flash file, Open Office Writer document, picture (png, jpg), PDF, SVG, multiple variants of (x)html, among other options.
Pro Can copy entire hierarchy to/from Word with a simple copy/paste action
Freemind allows quickly copying over structure of the mindmap as a bulleted, tab-indented list starting at the node selected. It can also take a bulleted, tab-indented list and create a mindmap from it.
Pro Fullscreen mode available with a patch
A user-contributed patch is available that adds fullscreen mode to FreeMind.
Pro Good documentation
Pro Cross-platform desktop and mobile
Works on Windows, OS X, Linux, iOS and Android.
Pro Revision control
Pro Supports media files, recognizes URLs and commands
Freemind accepts drag-and-drop for any kind of file, URL or command as part of the mindmap. Files it recognizes, like images, will be displayed. Other files will open in a separate, appropriate application. URLs, links to folders, and executable commands pasted in will be recognized and turned in to clickable links.