I've come to the conclusion that cops are almost totally worthless for bike theft. It's so rampant in most communities that they appear to really not give a s**t. The CL thing might work.... However, are you prepared to run them down and prove they have your stolen bike?

If you do run an ad, and suspected thieves do call, then and only you might get some police support. You'd have to ask the suspect to bring the bike, and them somehow be able to hold onto it while either the perp is questioned, a cop inspected it for the serial number, or perp runs away knowing he's caught.

I'm basing all this on a similar situation we had around here. A friend's whitewater raft and trailer was stolen out of his driveway. More friends were watching CL regionally, and sure enough it it turned up on CL six months later. Friend B went over to act like a pretend buyer, and was able to identify it (it was a special edition with some unusual markings). Then and only then the sheriff got involved and came with Friend B when he went back to "purchase" it. They were pretty lucky, though.