QR code & advertising

Recently I and two other girls designed a poster and the client required us to put a QR code at the corner. Not coincidently, I saw lots of posters,flyers,magazines with QR code on them. I think QR code change my understanding of advertising by providing an interesting interactive way on paper media. It works well in a mobile era like nowadays.
Firstly, it provides a strong incentive to interact based on passive paper media. I feel I'm always curious about  contents contained in the small odd squares. I like the feeling of discovering something myself. And I feel brands with QR code are cool and trendy.I have positive attitude towards brands on advertising with QR code even without knowing the brands thoroughly.
Secondly,its existence is combined with the smart phone apps QR reader.Users with a camera phone equipped with the correct reader application can scan the image of the QR code to display text, contact information, connect to a wireless network or open a web page in the telephone's browser. The implication is that advertisers don't need to create contents for mobile phones. Instead, the users will find the content themselves.It's an unobtrusive way to put advertising on mobile platforms. It might work pretty well when people see ads with QR code on bus stops,waiting room, etc, where people more easily feel bored.
Besides the information access function, QR code work as an invitation of certain events. People interested in certain events just need to scan the QR code and then they join in. It's quick,easy way to catch people's attention and interest. What's more, people could join in and win prizes just by their cellphone. People might feel more willing to participant if the entree is easy and the prize is rewarding. There is an example where people could buy grocery goods simply by scanning QR in subway station and ordered online in Korea. 
All in all, I think QR code provides new interactive opportunity as well as bridging the traditional paper media with mobile media. And the characteristic of it- exclusive, complicated but cool themsleves could influence viewers'  attitude towards brands.