For years, everyone in the radio frequency identification industry has been searching for the killer application for this exciting new technology. And there it was, all along, right under our noses... or perhaps I should say, knees: sorting socks!

OK, maybe the killer app is not sorting socks, but Swiss entrepreneur Samy Liechti thinks there is a business in being able to match pairs of black stocks out of a pile of laundry. In 1994, he founded Blacksocks, a subscription service that mails new pairs of black socks to business types at regular intervals. Now, he's introduced Smarter Socks—black socks that come with Near Field Communication (NFC) transponders attached to them, as well as an NFC reader that works with a person's Apple iPhone via Bluetooth. There's a Blacksocks app you can download for free from iTunes, in fact.

I am not making this up.

The app allows a user to read one NFC tag and then wave the reader around other pairs of socks until finding its exact match. Because the iPhone has no built-in NFC reader, you will need to utilize a Blacksocks NFC reader, and you will also require an Internet connection so the iPhone can access Blacksocks' server and locate the unique ID number of the particular sock for which you are searching.

"Together, the Sock Sorter we have developed and our iPhone app mean that nothing can go wrong and your iPhone can communicate with your socks, " the Web site explains.

It seems a little cumbersome, but it's all in the pursuit of the perfect pair of socks. The app comes with a tool to determine when your socks are worn to the point at which they need to be discarded. How much is it? You can receive the NFC reader and 10 pairs of fine black socks (made in Milan, the company reports) for $189.