QR (quick response) codes are 2-D codes your smart phone can read which then triggers an action (like opening a URL). They require an app on your phone such as the ScanLife Barcode Reader.
There has been talk of QR codes used by restaurants so you can scan a wrapper and learn about things like nutrition content. Musicians report seeing QR codes in magazine ads that in some cases trigger a video of a noted artist playing a specific brand of guitar.
QR codes first gained popularity in Japan where smart phones are especially common. Not only to they appeal to “techies” and early adopters, but they are often a tool of fast-moving marketers who use them everywhere from billboards to business cards. Have you seen any?