QR (Quick Response) codes are a bit like barcodes, but instead of needing a barcode scanner to read them, you can use a mobile phone camera (either one with the software built in, like the Nokia N95, or by downloading a code reader onto your phone). The QR codes generally contain a machine readable version of a URL, so that your camera decodes the image and opens up the relevant website in your phone's web-browser.
It's essentially a physical hyperlink, or 'hardlink'. (So if you use your phone to take a picture of the code above, it should shoot your phone's web-browser across to the best design blog in town.)
This tech is big in Japan (where mobile technology is generally a few leaps and bounds beyond ours), having been developed in 1994 by Denso Wave. But it's gradually popping up over here, and will probably become more and more popular as phone technology catches up. (Nokia pre-installs code readers on its N93, N93i, N95 and E90 phones, and this page from their site lists places you can download readers for their other phones.)
If you're not rocking a Nokia, Kaywa produce one of the leading code readers, which you can try installing on your phone – though it doesn't work on iPhones yet. (But if you've been naughty and have a jailbroken iPhone, you can download the iMatrix reader.)
You can also create your own QR code over with Kaywa.
People are finding all sorts of interesting ways to play with the codes. Here's just a few of the bits we've discovered so far:
Semapedia is encouraging people to create QR codes as stickers to put up at physical spaces, linking back to the relevant Wikipedia articles. (The Semapedia site has also got a useful drop down list of phone makes and models, linking to the code readers that work with them.)
On a bit of a sidenote, we reckon this area is potentially a gold mine for networking events. We've always wanted to be able to pass a scanner across a crowd of people at a party to see who's who. We can really see a market for a small smart badge versions of QR codes, so that you can advertise yourself to a room. And since you get to choose which webpage the badge links to, you're in control of the information people can access about you - it could be a page you've posted just for that event, your business website, or even something entirely unrelated...
There's another Facebook application "Add to Friends" Gear which does a similar thing, creating some rather dubiously designed stuff that features links to your profile.
2d-code.co.uk is a blog with lots of stuff about QR codes, including a story about how you can screw with your QR codes to make them look more intersting, as they allow for up to 30% deterioration of the code while remaining readable. Which means the BBC could stick their name into their code.
qrcode.es is a Spanish site all about QR codes, inluding a feature about using them as an updated version of laserquest in a battle round a shopping store, and a short story competition, where you have to create short stories (just 100 characters including spaces) that can be embedded in QR codes.
They also do some t-shirts and products, inluding this baby's bib which decodes as "My parents are freaks. Please, adopt me!". Which is, frankly, genius.
And finally, there's a (currently fairly shallow) Flickr pool of people doing interesting stuff (stamps, stickers, artworks) with the codes .
We love these little linksplats.
Admittedly at the moment they tend to be ham-fistedly stuck onto adverts and posters rather than properly integrated, which looks rubbish; but hopefully as people start playing with them more and more, they'll start to appear in more refined and witty ways.