DrawPile - Drawpile is a drawing program that lets you share the canvas with other users in real time.
PaintBerri - PaintBerri is a free art site that offers an awesome oekaki community.
QueekyPaint - QueekyPaint is a unique browser-based drawing tool for creating animated drawings online.
okekai - A small community site where you can draw, animate, and chat through pictures all for free
Aggie.io - Draw a picture together with your friends in real-time over the internet in your browser.
Brush Ninja - Hand-drawn Animated Gif Creator