Drawpile is a drawing program that lets you share the canvas with other users in real time.

Some feature highlights:

• Runs on Linux, Windows and OSX
• Shared canvas using the built-in server or a dedicated server
• Record, play back and export drawing sessions
• Simple animation support
• Layers and blending modes
• Text layers
• Supports pressure sensitive Wacom tablets
• Built-in chat
• Supports OpenRaster file format
• Encrypted connections using SSL
• Automatic port forwarding with UPnP