The Doodle board is one of Xat's features. It's pretty much a pen a paper. That's it. The "Pen" has 40 preset colours and a size adjuster. There is no earaser. In order to eliminate any mistakes, you need to choose the background area colour. There is also a way to create your colours, but that's too much trouble.
An Example of Doodle
An example of Doodle in use.
A Friendly Game Of Hang-Jed on doodle.
Typer will allow you to type words on the doodle and even on GIMP and other stuff. Be sure to suspend hotkeys by clicking the AB icon on the taskbar on the right side.
Link to Typer
Link to save/use Offline doodle(ofc the use wouldn't be offline, but I don't think you'd be connected with anyone)
BZPC Doodle ComixEdit
Starting on Aug 18 2013, the BZPCians began makking comix in the doodlebox.