Taken Out of Context? You might be part of a contextual ad program without even knowing it.

Are you investing in pay-per-click advertising on search engines such as Google or Overture? If so, your paid listings might appear on other Web sites-but not on their search results page, and not for the keywords you bid on. Your ads may appear on site content pages deemed relevant to your ads.

A few search engines automatically enroll their keyword search advertisers in a "contextual advertising" program. Let's say you're bidding on keywords related to the phrase "dog collar," and you reference this phrase in your ad listing copy. Your listing may appear on the dog page of PetPlace.com(under "Ads by Google"), a publisher of Google's contextual advertising program.

Appearing on Web pages instead of in the sites' search results is an extra shot of visibility. Contextual advertisers don't wait for consumers to query the keywords they've bid on. But how do contextual ads perform?

Jason Butcher, 34-year-old president of Synergy Diet LLCin Pasadena, California, reports that his company's average customer order is $133 from Google's contextual ads, compared to $56 from Google's search ads. His marketing costs are about the same for each program. "Google is our most profitable marketing tool [online] or offline," Butcher says. "And Google's contextual ad sales are twice those of search." Synergy Diet has advertised its low-carb foods on the radio and in local newspapers, magazines, pay-per-click search engines and online affiliate programs.

To determine the profitability of your contextual and search ads, track their sales separately. Create two campaigns, then disable either contextual or search ads within each campaign. This allows you to set different bid amounts, write different listing copy, and track resulting sales.

Butcher recommends writing narrowly focused copy for contextual ads. Write about one subject, product or idea. He believes that contextual ad viewers are in "shopping mode," but if your ad is too general, you'll get clicks but few orders.

Returning to the dog example, a pet supply store might bid on "dog collar." Using "For all your pet supply needs" as ad copy may bring in shoppers who see this listing appear as a search result. But if the listing appears on a Web page about dog training, this general ad copy won't likely perform.

Advertisers who've been unknowingly enrolled in a contextual ad program and aren't managing it separately from search could be perplexed if their ad profits have recently fallen.

Visit the search engines' sites to learn more about contextual advertising and how to manage it. Overture refers to its program as Content Match; Google's program is called AdSense. Kanoodle launched ContextTarget, which thankfully is a separate program from search. FindWhat.comwas testing the program at press time, and information was not yet available.

Speaker and freelance writer Catherine Sedaowns an Internet marketing agency and is author ofSearch Engine Advertising.