Jason Santa Maria started a sketchbook group on flickr.
Sketchbooks are not about being a good artist, they’re about being a good thinker. In the spirit of awareness, I’ve set up a Flickr group for this very purpose. Post one, and only one, spread/page from your sketchbook. It’s always fun to see how everyone else’s mind works.
Read more about it in Jason's post Pretty Sketchy.