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.

MSN Live Search services include MSN Hotmail, MSN Messenger, MSN Search, Groups, Shopping, and Personal Finance.

Microsoft Digital Advertising Solutions provides solutions for marketers to connect with their target consumers across multiple digital touchpoints.

Google provides web search as well as specialized search.

Google News (including archives)
Google Patents
Google Product Search
Google Scholar (Scholarly papers)
Google Special Searches (including Public Service & Government)
Google Video Search

Yahoo! provides search services as well as a variety of marketing products.

Local Advertising 
Target prospective customers searching for businesses in your area on Yahoo! Local—and drive them to your web pages or physical location.

Search Submit
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Product Submit 
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Travel Submit 
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Email Marketing 
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Technology Solutions
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Kontera is an online ad network that provides in-text advertising and information services based on text and content analysis technology that maximizes relevancy and yield for online users, publishers, and advertisers.

The company’s flagship product, ContentLink™, finds contextually relevant keywords on a publisher’s web page in real-time and automatically matches them to relevant ads and information.

Vibrant Media is an online ad network. Their In-Text Solutions highlight words in web content, gaining mindshare by aligning relevant information with the words that define brands and products.

Vibrant In-Text Solutions uses the IntelliTXT technology to ensure that all information is precisely targeted and contextually relevant.

Tremor Media provides advertisers with in-banner and in-stream video advertising opportunities on top-tier publisher sites with a combined 92 million unique visitors per month. Tremor provides publishers with a full suite of products and services to monetize streaming video and maximize ROI.

AzoogleAds is an end-to-end online marketing solutions provider for advertisers, publishers and online affiliates. AzoogleAds generates the traffic through its affiliate network, its proprietary search technologies and optimization, and its in-house CPM/CPA/CPC Media Buying and the company’s unparalleled industry expertise.

GlobalSpec offers  online advertising programs for B2B companies targeting the engineering, technical and industrial communities.

The Google AdWords Conversion Optimizer enables advertisers to meet ROI objectives and minimize conversion costs by automatically managing your bids according to a maximum CPA goal.

To use the optimizer advertisers must have received at least 200 conversions in the last 30 days in order to make accurate predictions about future conversion rates.