It looks like mobile 2D barcodes are starting to catch on in Europe at least. When I was in Japan a couple of years ago they were everywhere, on handbills, maps, business cards, product packaging and in magazines. The idea is that you point a camera phone at a barcode and take a picture. Software in the phone decodes the image and takes you to a mobile website, downloads a ringtone or adds contact information to your phone's address book. Almost all Japanese phones come with code readers.
The rest of the world is starting to adopt this technology. Nokia is bundling a barcode reader with the E90, N93, N93i and N95 (including the US market N95-3). With millions of these phones in circulation we are finally at the point where if you put a barcode on something, there's actually a good chance that someone will spot it AND have a phone with a barcode reader. Marketers seem to be taking notice too, lately QR codes have appeared on British movie and TV series posters, car ads in Germany and in a South African newspaper. The BBC is using them on promotional materials and Google is putting them in print ads!
I think one of the best uses for barcodes is mobile website discovery. At WapReview.com, I've created a directory of over 1000 mobile sites which you can search and browse to find sites with a particular type of content or ones that just look interesting. That's good but how do you get those sites on your phone? You could just type in the URL but that's a hassle on a phone keypad. Or you could point your phone's browser at yeswap.com, a mobile portal that mirrors the directory structure of WapReview.com and is searchable. But now there's an easier way, every site on WapReview.com has a QR Code included as part of its listing. Here's an example:
It started when I found this great open source library for creating QR Codes, the same code format used in Japan and the most widely used type of mobile 2D codes in the world. The library is by Y. Swetake and it's pure PHP so it even works on my shared hosting where I can't install binaries.
Using the library I threw a little code together to display a 2D code along side each listing in the WapReview directory. So if you're browsing through the directory and see a site you'd like to try you can just snap it with your 2D reader equipped phone to load the site in your phone's browser. I did find that reading codes off a CRT monitor was hit or miss, only working about half the time, but with an LCD monitor it worked very reliably using the N95. Give it a try. If you don't have one of the Nokia's with a bundled reader there are several readers you can try:
Nokia offers a reader download for the N80.
For other phones, go to Semapedia.org, who's goal is to tag real world places with a 2D codes that point to a Wikipedia article about that place. Semapedia's homepage has a web form to help you find a reader compatible with your phone. If your phone is not listed on Semapedia here are several QR Code readers you can try:
Quickmark has readers for all S60 phones, most Windows Mobile devices and the SE P900 and P910.
There are a couple of Java ME readers from i-nigma and Kaywa.
If you want to create your own QR Codes you don't need to install Mr. Swetake 's code on a web server, there are a number of QR encoders on the web. Nokia has one as does Mowser.
I can't mention 2D codes with putting in a plug for Scott Shaffer's blog, The Pondering Primate which is all about what Scott calls, "Real World Hyperlinks" which includes both barcodes and NFC tags. Kaywa's blog, All About Mobile Life, is another good starting point for anyone interested to learning about 2D technology and the growing business opportunities around it.
If you do (or don't) find the 2D codes useful leave a comment. Also, if you find a reader that works on your phone I'd love to hear about it, particularly Java readers for mass market phones. I haven't found one that works on my Motorola i855. Kaywa's reader does work on a Sprint Samsung A920 I tried. You have to manually close the Kaywa reader before the browser will launch on the A920, it would be nice if the reader closed itself automatically, but it does reliably decode QR codes which is pretty impressive considering the phone only has a 1 MP camera.
Update: I got an email from Roger mentioning his blog, 2d code. I just took a look and agree 2d code is well worth visiting, in fact right on the front page I learned about two more QR Code readers. ZXING is an open source effort supporting J2ME (although it didn't work on the two Java phones I tried, a Samsung A920 anda Motorola i855) , J2SE, and Android! The other is iMatrix a native app for hacked iPhones.