You might not think about them much. When you do, it might be to decry the invasion of robot vomit onto every ad, billboard and poster. Still, the humble two-dimensional QR Code -- originally developed by a Toyota subsidiary to assist in automotive manufacturing -- has become ubiquitous.
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. They're ideal for short URLs, vCard contact info, SMS or phone call "triggers" for mobile pho
