A few years ago I had a Trek 720 stolen. I posted on
bikeforums.net and was advised to list my bike on
bikeindex.org. I did so and did recover the frame as a result about a year and a half later. Fortunately, I did have the serial number to list. Without that, I suspect the listing would not have been effective. Now, if I'm looking at a used bike to buy, I will search bikeindex to see if it might be listed.
Bill S
San Diego