Ambient Media... Any ideas?

My friends and I were constructing our final client presentation for the Vaseline campaign launch on Monday (more on that later...) and discussing the relatively new slither of jargon that is "ambient media". We thought that we had possibly stumbled upon some in looking at Nivea's "Give a big hand" campaign, whereby people can purchase a large foam glove to support those running the Cancer Research Race for Life. Whilst supporting a charity and a race, Nivea are placing a lot of adverts for their product (HAND cream!) in a concentrated area and (as inferred), the big hand relates to their product. Smart.

Even Wikipedia doesn't seem to know a lot about this phenomenon, can anyone provide me with a more concise definition?

I later found myself in the Range, where I discovered some unintentional 'Ambient Media'!! This inflatable playpen, designed to keep children in one place had been hung clumsily by the infallible marketing statement "NO EXIT". I'm sure this will encourage parents to buy one immediately. Whilst we're at it, let's get one for the in-laws as well!