What are some alternatives?
FreeMind - FreeMind is a premier free mind-mapping software written in Java.
XMind - XMind is a brainstorming and mind mapping application.
TheBrain - TheBrain: The Ultimate Digital Memory
MindManager - With MindManager, flexible mind maps promote freeform thinking and quick organization of ideas, so creativity and productivity can live in harmony.
Coggle - Coggle is a simple, beautiful, powerful way of structuring information.
Docear - Docear