SendMeHome is a new and free lost and found database. It works by having users register their personal effects with little stickers that have special "phone home" codes on them. If someone finds something you've lost with one of these codes on there they can plug it into the service and get whatever contact information you've left--hopefully bringing you and your lost iPod (or whatever) back together.
Similar programs for bicycles have existed for years, and there is definitely a rate of return, although it obviously depends on what you lost and who has found it. … Read more