It has been difficult for offline retailers to leverage the power of digital. Sure, QR codes were once promised as a creative way to help merchants do that, but it's been slow going (if it really ever got going at all).
One of the reasons that might have been an issue is because it has not been easy to create or track them with any accuracy but that is beginning to change.
Shopify recently introduced Shopcodes, an app that will allow customers of Shopify merchants to scan codes and buy products using their mobile phone.
QR codes can be created from the Shopify dashboard and merchants can customize it with links to a specific product page or the shopping card page. Merchants can also add discounts to the Shopcodes they create or make changes (adding discounts, including additional/exclusive information, etc).
Once the codes are created, they can be used in the digital or physical world. You can download the codes, print them and place them on products, offline ads, or windows in your brick and mortar store. When customers scan them, they can find out more about your store, products or be directed to your Shopify store - effectively bridging the gap between online and the brick-and-mortar world.