Today’s invention is street advertising hoardings which get themselves pasted online too.
Adverts on street-level billboards would have a dotted line figure (or figures) included.
People would have their photo taken in this amusing or incongrous setting, so that the image would be posted on say their facebook profile and shared.
The reposting of the image would allow many more people to see the original poster. This process could also result in prizes for those appearing in the most popular images of a given advertisement.
Another version might allow the facial feature distribution of a person imaged to be used as a code to select some additional message or bonus content to be injected into the final, online image.
So now see this, which is not so communicable, I suspect, as the faces of people you know http://www.gizmodo.co.uk/2012/06/go-compare-defaces-own-ads-so-you-dont-have-to/