QR codes can help you promote your business. You can code any information you want including contact info,your business locations, email addresses, YouTube videos and so on. I implement this cool feature in my apps using snappii technology. They are really helpful if you need a mobile app but don't have programming skills at all.
QR tags are wonderful but you still need to expose than to everyone. A great platform for that is the new website www.whocanihire.com which is a platform for small business to market themselves (QR tags) through social media potentially reaching thousands of customers.