I was reading a good overview of QR codes at http://www.getelastic.com/qr-codes today.
But i feel the comments about roadblocks was misinformed.
"QR Code Roadblocks
Though “big in Japan,” the roadblocks to QR code popularity in North America are that many phones don’t have QR code readers,"
My response is
The roadblocks to QR adoption isn't not having readers pre-installed though yes this does help to raise awareness but i bet you haven't used 'every' software app that resides on your current phone and a QR reader would just become 'another application'.
The real issue is that there are very few QR marketing campaigns where there is content/reward of any siginificant value to encourage mobile phone users to interact with the QR codes.
The Japanese market works because there is value in the QR campaigns and the content users can access.
The real roadblock to QR code adoption in the USA (and Australia), is dinosaur old school marketing/brand managaers who play it 'safe' (and if you are reading this thinking hey that's not me I'm just waiting for the number of readers deployed to increase then i'll roll out a QR campaign for my brand..... then yes I'm talking about you).
The first person to buy a fax machine was an idiot but the second one was a visionary.
It's time for brands to roll out content of value, if QR codes are the only way to access this value then your users will start to download readers.
Be a visionary not a dinosaur.