Creately: Online Diagramming and Design Tool

http://creately.com/
Creately, a free online diagramming and design application lets anyone create and collaborate on flow charts, wireframes, network diagrams, sitemaps and more. The key to Creately’s application is that it manages to harness the abilities and tools that traditional design and graphics software offer, but packages this functionality in an easy to use application that allows for collaboration between users.

The design features are varied but relatively easy to use. For example, "Contextual Toolbars" appear when you click on any object on the drawing canvas and depending on the object and its size will offer all the commonly used operations within the toolbar. Collaboration is another crucial part to the design process, says co-founder Charanjit Singh, so the startup built in commenting, sharing, publishing, embedding and the ability to publish directly to Twitter. Creately's free version lets users make an unlimited amount of public diagrams that can be published on Creately and visible to anyone. Free customers are restricted to a maximum of 5 collaborators and all diagrams will be published with the Creately logo. Diagrams can also be embedded and shared.