But the visual code application Luna has most invested in so far is one for the real estate industry. It is at least partially advertising-related. Brokers could print codes on the signs posted on properties they're selling. When drive-by home hunters stop and scan the code, it could trigger one of a number of actions. They could be taken to a WAP Web page listing for the property, given a phone number for the listing agent to call later - or it might automatically dial the agent's number right then.

"Part of the process is thinking these [options] through for each individual customer and helping them figure out precisely what they want to do - other than just showing more advertising," Hayden says.

Luna is "close to" launching two packaged QR-related software products: a tailored application for real estate and a more generic advertising application based on the tried-and-true Japanese model.

It's pretty hard to avoid the advertising angle with mobile QR (and other visual) codes, but some marketers are at least coming up with innovative ways to use the technology.

For example, Dentsu Canada, an ad agency in Toronto, came up with a novel contest-related campaign for Vespa, the Italian scooter manufacturer. (Dentsu's Japanese parent, it's interesting to note, is credited with pioneering the use of QR codes for advertising in Japan.)

The firm plastered downtown Toronto streets last summer with pop-art posters showing an outline image of the iconic scooters, a QR code and the bold message, 'Scan me.' When consumers scanned the codes with their phone cameras, a message automatically popped up on their screen telling them whether they had won a prize. (The posters also directed them to a URL where they could download the reader software if they didn't already have it.)

A spokesperson for Canadian Scooter Corp., Vespa's distributor, told us the campaign was very local and short-lived but "quite successful. We were happy with the results and would definitely be open to doing something similar in the future. However, we don't currently have another QR campaign planned."

All of which, ultimately, tells us nothing about the future of mobile visual code reading in North America. The technology works and consumers who have used it seem to like it. It's also clear it has a multitude of possible uses - albeit with advertising-related applications cropping up more than any other.

But is that enough to guarantee the technology will be embraced by consumers, carriers, device manufacturers - advertisers? We'll see.