Howdy,
I’m a big fan of sketchbooks on other forums. They’re not works in progress and they’re not tests, they’re just a running record of quick works or ideas.
Conceptart.org has a full sketchbook section, where you can subscribe to favorite sketchbook if you choose.
I think it would be a good idea to have a sub forum for blenderartists.org for this type of thing. Does anyone else agree?