It's happened before and it will happen again---the inappropriate pairing of an ad and content---in this case an ad for two upscale communities at website "PutYourFeetUp.com", inadvertently paired with a grisly story of severed human feet washing up on a beach in British Columbia.

Contextual advertising is the analysis of keywords and page content to match a page with relevant ads. Unfortunately, the algorithms that govern the placement of advertising versus page content can only filter out so much, and the result is the occasional creepy pairing seen above.

The companies offering contextual advertising, among them Google AdSense, Overture's ContentMatch, and Adsdaq as well as news and information sites and others are surely trying to find away to avoid these unfortunate placements. It's not an easy problem to solve.

So---does this mean you shouldn't use contextual advertising. Not at all. Just be aware that sometimes s**t happens.