The first person I ever saw using a QR code in an email signature line was Jarad Miller, around the time he was moving into his current role with United Airlines as managing director for self-service and emerging technology.
At the time I was quick to follow; it worked well, but primarily for the novelty value of customers asking me to explain QR codes as it enabled me to get right into a good conversation on mobile commerce with potential and existing customers.
I recount that story in order to introduce the purpose of the article below.
Read full story at: http://www.tnooz.com/2011/11/24/mobile/how-mobile-payments-and-digital-wallets-will-open-up-new-opportunities-in-travel/