If gate passes or admission tickets were to have a millennial cousin, its name would be QR code. A QR code, or quick response code, is a two-dimensional barcode which can be read by webcams or smart phones. Smart phones require a free app to scan the barcode. When the barcode is scanned, information appears on the phone screen or computer. This information can be text, a web address, an email address or a video. It was originally invented in 1994 by Denso Wave, a Toyota subsidiary, as a way to track vehicles as they were assembled, and to scan components at high speeds

QR codes have long since expanded their usefulness beyond the automotive industry. They're used today in everything from inventory tracking, to shipping and logistics, to online ticketing. Bands put them on fliers to link to their videos on YouTube or set reminders for upcoming shows. Businesses use it to put Google Maps directions on a business card or send a text/email to the company helpline. One enterprising wildlife refuge in Sanibel, Florida has installed the codes on signs along hiking trails and programmed them with information about the local fauna. Advertisers who want you to find out more about their products online simply print a two-dimensional barcode in the corner of their ads. Just point your cellphone at the code, scan it in, and your phone browser will automatically read the code and take you there instantly, no need to type in a tedious URL or anything like that. It's especially convenient for billboards, posters, and other ads you catch site of while you're on the move.

However, QR codes aren't all fun and games attached to information. The codes can also be used to transmit malicious code, in what's known as "attagging." Since anyone can create the codes, it's easy to write a bit of malware, put it in a QR code, and slap that code over a legitimate tag. Some unsuspecting millennial scans the bad code and, if their permissions are set too loosely, the code could give itself access to everything from the camera to the contacts to the GPS data. Or it could connect to an infection site loaded with browser exploits. The phone could become part of a bot net, or be used to send unauthorized texts.

With smart phone apps like the Philippines' Booky and Singapore's Honestbee as well as Sephora, Walmart and other western companies utilizing QR codes to promote special offers, it seems like QR codes are here to stay and possibly become more intertwined in our shopping experience than ever considered.