I've worked on this ideal platform for communication for 7 years and today so proudly launching it.
My app lets you call your friends for free. From that you two can talk & draw & view web/Dropbox content together. All in real time.
The idea for the app is pretty new, falling in a category between messaging and collaboration.
Have any question? just ask me here.
Link to download my app: https://itunes.apple.com/us/app/voxypad/id827004799?mt=8