So to make these work you need the following:
- A smartphone, be it of the Apple or Android variety.
- An app that can translate the QR code to something meaningful.
So for me I need to start an app on my iPhone, photograph the code and wait and see if something happens. If it works it eventually directs me to a bit of web content related to the advert the code is on. On my iPhone this takes a couple of minutes (maybe the software and hardware are slow) but why not just put the URL on the advert instead. Its a lot quicker to copy this down into your browser.
Maybe I'm wrong, who knows?