No one makes the most of what they have like the Japanese. Not just in electronics and technology, but also in advertising. It's a known fact that Tokyo is one of the most (if not the most) populous city in the world with an extensive rail network. What best place can you capture the eye-balls of the people other than railway stations. Result: All the walls, floors, hand-rails etc. have become some form of billboards - but aesthetically pleasing to the eye.
Recently Apple carried out an expensive campaign of having IPOD Nanos stuck on the walls (using some magnetic technique), letting the passers-by to have a look and feel of the product. In addition, they have pasted a Quick Response (QR) code sticker at the back, so that the tech-savvy people can have a look at the code of the Nano. The QR codes are used in all the advertisements to get more information about the advertiser and the advertised product than what is displayed in the actual advertisements.
Know more about Quick Response (QR) code. To see the entire article about the ad-campaigns happening in Japan, go to Pingmag. Wired News calls the same as Madvertising.