Unfortunately, some marketers seem to think that putting the codes on highway billboards (where you can't really pull out your phone to scan them as you're driving by at 55 MPH) or on subway platforms (the underground thing, not so much with the 3G data) is helpful and clever - it's not. I've used them on name badges for customized scoring forms and on stickers in out-of-the-way corners as scavenger hunt targets.

They're ideal for short URLs, vCard contact info, SMS or phone call 'triggers' for mobile phones, and plenty of other cool tricks.

QR Codes can deliver almost any kind of digital data, as long as it fits within the code's capacity the densest versions of the barcodes can hold more than 4,000 ASCII characters, but most of the codes you see in public are much less info-packed. Still, the humble two-dimensional QR Code - originally developed by a Toyota subsidiary to assist in automotive manufacturing - has become ubiquitous. When you do, it might be to decry the invasion of robot vomit onto every ad, billboard and poster.

Macbook scan qr code wifi