As long as people are standing around, they may as well be looking at your ad, right? Major urban centers with subway and commuter rail systems offer a large captive audience. Take advantage of it with platform posters-large, high-visibility messages.

Depending upon the market, these posters can be glued to fixed displays, much like a mini billboard. They entertain commuters 24/7, never take a bathroom break and don't expect tips. Now that's a bargain.