Kayuda is a web-based visual wiki / mind-mapping / brainstorming / writing tool. It is collaborative, allowing thousands of users to work together at a time. It is free. Note: Wotan LLC, creator of Kayuda, is a U.S. based (not London-based) company. Someone outside the company posted the Kayuda entry here with no description or information and I created this account to correct the profile. I had to give a UK post code in order to sign up. --David Storrs, CEO of Wotan LLC