Coccinella

Coccinella provides sketch to explain your words, collaborate on diagrams, enter mathematical formulas like on paper, and draw together for fun. Coccinella is a free and open-source cross-platform communication tool with a built in whiteboard for improved collaboration with other people. It have the features like multi-lingual and internationalized, plugin system, MeBeam plugin, search people in dictionary, avatars and emoticons, themes, and secured connections (TLS and SASL).