Take this recent example from Vodafone.

Aside from the obvious downsides (user doesn't know where the link will take them, if it's compatible, link looks like gobbledegook, etc) there is a rather more interesting issue.

Goo.gl - along with many other URL shortners - give everyone access to your statistics.

Visiting http://goo.gl/NdVGI+ will let you see everything.

I don't know how many messages were sent out, so it's hard to calculate a response rate.

From the map, I can see the two target areas were UK and (unsurprisingly) Greece. There are a few hits in other countries - that could just be people connecting via WiFi networks routed through that country.

There are also a few hits from iPhones - suggesting either the targeting wasn't accurate, or people are spoofing the iOS user agent.

Still, it's an interesting insight into Vodafone's marketing.

Last year, I noticed this QR code as I passed through San Francisco Airport.

The code goes to a TSA site (albeit non-mobile), which is odd, as the TSA do have a capable mobile site.

What I find most curious is that the TSA are using the Goo.gl URL shortener.

This is a bad idea for two reasons.

1. How does a user know where the code is going to take them? The URL "goo.gl/Qrlx1" could lead literally anywhere. A security minded organisation should always use their own domain name when creating a QR code.
2. Google short URLs allow anyone to see your QR code's usage statistics.

So, let's see how the TSA checkpoint QR code does.

Interesting to note that there are a few people prepared to pay roaming data charges to view the site. I've no idea if this exact QR code is at other airports, but it's gathering around 80 scans per day.

You can read more about the TSA's use of QR codes at their press centre.