Create a finite canvas. Use this if you want to work on a traditional art piece with your friends and don't need infinite space. This will feel familiar to iScribble.
Create a infinite board where you can draw and chat with your friends. This works well for roleplaying. This will feel familiar to malmal.io
Create a community where you can invite many people, plan events, post to the community gallery and much more. A community can have multiple boards attached to it. You need at least 50 karma to create a community.
An infinite board that is optimized for a whiteboard-like experience, where you can quickly move stuff around, create mindmaps, etc...