My respect for use the java stack, I like it. Here another guy to tried to build his own whiteboard a few years ago http://notephy.com , I'm just searching a solid support to audio recording with webrtc to improve it.
I'm working on Braph, a parametric search engine and a model-as-a-service solution. It's about classes and instances, where you can save your data with certain properties and search by its characteristics. In the demo I create a Pokemon class and create many instances, even with relations between them (evolution), then I could search a pokemon by its weight or evolution. http://www.youtube.com/watch?v=CfOvGYEYJq0