I give my colleague Charles Golvin credit for finding this article on the official Google blog. I'll be working on a report on the intersection of social and mobile in early 2010 so please send me more examples if you have some. I'm especially interested in the role of social/mobile in the Retail environment.
Google is mailing out storefront window stickers to 100,000 local businesses in the US. (see their blog post for complete information). If you have the right type of phone and supporting software, you can take a photo of the code on the sticker (see below) and you'll be taken to that business' PlacePage on the Web. The service will show available coupons, allow for ratings, get reviews, etc.
Here is their post on the applications that work with the service:
To scan the codes, you'll need a phone with a camera and an app that can read QR codes. For Android-powered devices, including the Droid by Motorola, we recommend using the free Barcode Scanner app. For iPhone, we have found the $1.99 QuickMark app to work best, and starting today, we're partnering with QuickMark to offer the app for free for the first 40,000 downloads. For other devices, we recommend searching for "QR reader" in your app marketplace, if it has one, or searching for the model of you phone and [qr reader] on Google. BeeTagg and NeoReader are two other apps that we've found to work well with the decals.
The more entities using these codes and teaching consumers how to pull information about a local place or tourist attraction from the Web on their phones, the faster consumer awareness and adoption will grow.
Here's a copy of the sticker from the same blog site: