Designed as a high-tech marketing resource, QR (quick response) codes have many useful applications. These (usually) black-and-white algorithmic codes are gateways to a potential multimedia nirvana.

Without an easy interface for clicking through to purchase, audio and video ads have, until recently, been best suited to upper-funnel brand-awareness campaigns rather than direct response. But now, ...

Let me come clean: For way too long now, I’ve been excited about the 2D optical code format called QR Code. I even convinced TidBITS to put one on every article page for a while. I don’t get a ...