In a patent filing Google has revealed that it is looking into entering the physical advertising industry. The patent filing itself alludes to placing adverts on billboards, with the primary innovation being that they're interactive and connected to the internet -- what, you didn't really believe that Google would go in for static ads did you? The system apparently works by only advertising products that are available and in stock within stores in the local area. Stores will be able to buy advertising on these local electronic billboards through a similar system to how AdSense currently works: by logging into a computer and buying them. One of the key positive developments -- at least for busy consumers -- is that once stock of the product has run out, the advertised project on display automatically switches onto the next one that's in stock. This whole project relies greatly on there being adequate infrastructure for Google to make a return (which obviously isn't a problem when it comes to the internet), so this patent is far from an assurance that you'll be seeing "Ads by Goooooogle" reminding you to pick up some milk from your local 7-Eleven any time soon.