Visual tags are something already common in Japan. It isn't here, as this link to an Intel Research Paper shows:
New Uses for Camera Phones

There are many scenarios where the combination of visual tags and camera phones can be employed. Maybe you're walking down a city street and see a poster for a movie or a play. On the poster is a visual tag. By using a camera phone, you could click on the visual tag to get more information on the film. Additionally, there may be an option to buy your tickets right then and there.

[...]

Visual tags encode information in two parts: a service identifier and a data block. The service identifier encodes the name of the Bluetooth service to which a tag relates. The data block contains a few bits of application-specific information that are used to identify a particular tag.

PS: SpotCode reader is available for download at the High Energy Magic Web site

See also:
Linking the Web to Real Space via your Camera Phone