Windows: If you're looking for a lightweight mind-mapping tool to tuck on your flash drive, Bluemind is a speedy option with easy keyboard and GUI navigation, plenty of customisation options and support for multi-format exporting.
Click on the image above for a closer look.
Bluemind doesn't add anything to the mind-mapping universe that isn't already there, but it is very speedy. You don't need to install it, it can run as a portable app, and keyboard-based topic and sub-topic creation is a snap using the TAB and arrow keys to quickly create and navigate new topics. You can customise the appearance of Bluemind by changing the colour of mind map nodes, their padding, their shapes, the link colour and style, and other details. You can also navigate the mind map like an outline using the Objects pane beside the main window. When it comes time to save you can save the file in the Bluemind mind map format or export it as an image — in common formats like PNG, JPEG and more — or in outline format as a TXT file.
On a personal note, I try out every single portable mind-mapping application I come across. I use mind-mapping applications in my university classroom and so many of them are needlessly complicated and lack natural-feeling keyboard shortcuts. Bluemind is my new mind-mapping tool for use in group brainstorming sessions where a mix of computer savvy and computer semi-literates will need to use it quickly and efficiently.
Bluemind is a free, portable and Windows-only tool. The Bluemind site is written in Chinese; click on the translation link below to see it translated into English. For more mind-mapping tools check out the Hive Five on Best Mind Mapping Applications.