This is a feature we've had for a while but we thought we'd share it with you all as it is something you really have to discover to know about.
Our 404 page (The page that tells you there has been an error if you try to go to a page on our website that doesn't exist) also functions as a sort of search.
For example, try going to http://threadless.com/zombie. Since that page does not exist, it does a search for products and submissions containing that part of the URL. You'll see there are 2 products and many submissions with the word "zombie" in them. If the search finds 1 product with the keyword, it will even take you directly to that product page (ie: http://threadless.com/donkey.
So, if you're ever looking for a submission or a product in a hurry and can't be troubled to go browse through a few pages to find it, just type threadless.com/keyword into your browser and we'll help you find it!