Threadless.com is the phenomenally successful T-shirt company with more than 4 million tees sold since it began in 2000. It pioneered the online business model of crowd-sourced or community-driven design, in which people submit designs that are voted on by the site's 1 million users and printed. Over the past 10 years, the company has amassed a vast archive of very cool, very hip, and often very entertaining designs, and Threadless is a spectacular...