What are some alternatives?
XMind - XMind is a brainstorming and mind mapping application.
IdeaLab by Collective Innovation - Enterprise software to increase internal innovation through collaboration. Use internally or in an open innovation process. Get better ideas, make faster decisions.
MindMeister - Create, share and collaboratively work on mind maps with MindMeister, the leading online mind mapping software. Includes apps for iPhone, iPad and Android.
Ideator - Ideator helps you grow your idea and start a business.
MindManager - With MindManager, flexible mind maps promote freeform thinking and quick organization of ideas, so creativity and productivity can live in harmony.
Innovation Cloud - Innovation Cloud is a modular online end-to-end innovation management platform that enables you to innovate and create value in a flexible, engaging and rewarding way.