Semapedia This assumes there's a relevant Wikipedia article about some physical object such as, say, the White House and that some authorized person has "tagged" the site with a Semapedia tag, which today is typically a piece of paper with a type of bar code on it. Here's an example from the Flickr site.

Then someone with a supported mobile phone with a camera can take a picture of the tag. Then, using Semacode reader software loaded on the mobile, the mobile will connect and cough up the relevant Wikipedia article. A photo story about the process is here .