Cacoo – Create Diagrams Online with Real Time Collaboration
http://cacoo.com/

Cacoo is a user friendly online drawing tool that allows you to create a variety of diagrams such as site maps, wire frames, UML and network charts. All you need is a browser to easily create attractive diagrams for documents like Blogs, Wikis online. If you wish to edit/change the diagram you don’t need to upload it. It can be a joint simultaneous operation. Numerous users can work on and complete the same diagram simultaneously. Cacoo supports real time collaboration. Multiple users can simultaneously edit and complete a single diagram. Cacoo can be used free of charge. This has been added to the tools section of Research Resources Subject Tracer™ Information Blog.