Blippar is growing in popularity and is becoming a good alternative to QR codes as a method for joining print and online marketing, with Tesco and Waitrose already using this within their print advertisements.
The idea is "pause and blipp" - you install the Blippar app on your phone, and then hold up your phone to the screen/magazine to show an augmented reality layer. Which looks like this:
It offers a unique, interactive channel to merge print advertising with online marketing. The downside is that it's proprietary.