The concept of literal dumpster diving reminds me of a skit from a late '70's Saturday Night Live in which the camera's begin to roll on Weekend Update and catches Chevy Chase on the phone with his girlfriend and you hear him explaining "you don't actually blow on it, that's just an expression".....
I doubt that many of us dress in a kevlar suit and dive into a dumpster of mixed trash. But I admit to having recovered some nice finds from 'beside' the dumpster, or 'about to be thrown' into the dumpster.
Last week I scored a mid '80's Scott Arapahoe mountain bike from beside the dumpster. The recycling/transfer center near me has a new policy to actually encourage people not to throw away good stuff. If you think someone might want it, you place it next to the dumpster, and if it isn't taken home in 4 hours, the staff tosses it in. How's that for a great policy?