TheBrain
TheBrain, formerly branded PersonalBrain, is a mind mapping and personal knowledge base software from TheBrain Technologies. It uses a dynamic graphical interface that maps hierarchical and network relationships. It includes the ability to add links to Web pages and files as well as notes and events using a built-in calendar. It is cross-platform, available for Windows, Unix and Unix-like operating systems, and Mac OS X. It is available in a free edition as well as in commercial editions with additional features.