After losing the memory card at the park- I run into this- www.imhonest.com at OfficeMax. You buy the stickers and it gives you a free year's subscription and you stick it on to your stuff- it's got an ID # so that if people find your lost stuff, they can go to the website and they'll ship it back to you. (I think you have to pay for the shipping, though) Anyway, totally cool system! I have tagged my cell phone, my camera, my new memory card, the laptop, my keys, everything I can think of! (I would have done my sunglasses, but I ran out of stickers!) The stickers aren't all paper and flimsy- totally durable plastic-stuff!
Plus, the packaging says that the people who return your stuff get some sort of reward! So go get some- you can order the stickers online, or get them at OfficeMax (they're cheaper at OM).