Without warning or explanation, non-functional QR codes began appearing on random Facebook profiles earlier this week. After a few days of speculation, a new rumor has surfaced to give meaning to these scannable boxes of black and white squares. According to the latest leaked information, the QR codes will reportedly play a role in Facebook’s upcoming mobile application which will utilize codes for a new location-based service. Similar to and perhaps even in conjunction with Gowalla and Foursquare, these QR codes would let you check-in at businesses, like your local pub or favorite restaurant, and alert your Facebook friends to your location. Much of the success of this program hinges on the average Facebook user’s ability to understand and utilize QR code technology which, after the whole ReadWriteWeb login debacle, is highly questionable. Additional information on this new QR code-drive, location-based service is expected at Facebook’s f8 conference scheduled for the end of April.