Website for users to create accounts for their items, that when found another user can mark they found it.
IE: You've lost your wallet in San Francisco, and James finds it at the coffee house. But you've already gone home.
James will see your tag in the wallet, it has your unique ID, a QR code, as well as a statement asking him to log into ItemTrackr.com to mark the item as found.
He does so, and you are notified with his message "Hey, I found your wallet at Peet's on 7th ave! I'd like to get this back to you somehow! Here's my contact info:"
You arrange an address for him to ship your wallet to, and you send him an optional tip for the good deed.
James sees the use of the app, and signs up himself.