Have you ever struggled trying to type in a url on your iphone to get to a new website? Struggle no more with mine at least. Instead, snap a photo of this image and use a barcode reader to request the URL. My preferred reader is Barcodes in the iphone App Store.
Granted, the applicability of this to a blog like mine is a mere exercise in usability. But the extensibility of the idea is great - a performance group like Indyprov can post the code at events to let people in the know use it to easily get to their site to find out about future events. Animal rescue organizations can use these outside each kennel to provide details on each animal. What use could you put it to?
You can make your own barcode with Google Charts.
Thanks Rick Klau for the basic info on how to get started.