There are times when it seems you can identify the foundations of a sketcher. Architect, Illustrator or Painter, each with their own drawing dialect. By no means a perfect practice but often what seems to separate language styles is what Heinrich Wolflin described as linear versus painterly.
Some times this overly simple dichotomy can be really clear for example if you compare the sketches of Suhita Shirodkar, Pete Scully, and Simone Ridyard . Though other times the definition seem far less obvious.
Chris Carter, Monument Square, Portland Maine
Julle Bolus, Vintage Bookshop, London England
Nichegosebe, Kadashi, Moscow Russia
The USK Flickr page has a surge of new participant so be sure to check out some the wonderful submission
Also, check out the USK Flickr Weekly themes, this is a great exercise to help inspire your daily sketching habits, this week it is Street lighting