product review :: Lenstag
I recently discovered Lenstag, a free service that protects camera gear and images. I registered my camera and lenses, using my cell phone to take photos of the serial numbers (which is one of the methods of completing the registration of your gear). As noted on the site, it took a few days for my gear to be marked as verified.
Lenstag is a security blanket for my camera gear. It won't prevent theft but it does identify the gear as mine; in the event that it is stolen it gives me a way to flag it. I know, flagging gear as stolen doesn't mean it will be recovered but I suspect that the more people use this service the more protection will be provided.
According to the Lenstag web site the gear rental companies BorrowLenses and LensRentals both register their gear with Lenstag. That feels like a pretty solid recommendation to me.