I've posted a few bills. Never got a hit. If I get a bill with a Wheresgeorge stamp I do go check where it came from.
i mark all my bills with wheresgeorge. i entered about 150 bills and gotten 1 hit. i started in august, it takes about 6 months to really start getting hits.
I don't do WG but I do stamp dollar bills with various political slogans. I have put well over a thousand into circulation.