When you pick up a magazine or newspaper, you want to know whether what you’re reading was written to inform you or to sell you. It has long been a publishing tradition to clearly separate editorial content from advertising material. Both have their purpose and their usefulness, but both have their place.

The same principle applies to the brave new world of online publishing, although norms and practices are still emerging. This applies equally to Web pages and to search engines (the technology that often gets people to Web pages).

Search engines have been criticized for not clearly indicating when sites appear prominently in results lists because they’re relevant or because these sites paid the search engine for their advantageous position.

Organizations such as Consumers Union (http://www.consumersunion.org), which publishes Consumer Reports magazine; Ralph Nader’s Commercial Alert (http://www.commercialalert.org); and the Federal Trade Commission (http://www.ftc.gov) have been vocal in expressing the importance for search sites to fully disclose when search results are paid for.

The top search sites have made improvements here, as Consumer Reports WebWatch (http://www.consumerwebwatch.org) has pointed out. Google, for instance, places paid listings under one of two “Sponsored Links” headings—one at the top of the page in a shaded box and the other to the right of the page. Yahoo! does the same, although it calls its headings “Sponsor Results.”

If you’re a consumer, does it made sense to click on these paid links when looking for information? If you’re a business, does it make sense to budget marketing dollars for paid placement?

Kevin Lee thinks so, in both cases. Lee is the most visible expert in the country on paid search. He writes a weekly column on the subject for ClickZ (http://www.clickz.com), the well-regarded free online publication about online marketing. He also heads up Did-it Search Marketing (http://www.did-it.com), a New York City-based search engine marketing firm, and chairs SEMPO (Search Engine Marketing Professional Organization; http://www.sempo.org).

Before talking with Lee, I was skeptical. I mostly ignore paid links, as I suspect many consumers do. I also understood that Lee has a vested interest in promoting paid search. But, like he does in his columns, he presented some powerful arguments in support of paid search for consumers and businesses alike.

First off, it’s a big business. According to Lee, these textual ad links generate more than $4 billion in revenue a year for search engines. If the links didn’t work, companies wouldn’t be paying search sites this kind of money.

For businesses, Lee said, paid search makes sense because it gives you more control than “organic search” (unpaid search results). “You test, and if it doesn’t work, you cancel.”

For consumers, paying attention to paid links makes sense because they can be as or more relevant than unpaid links. Lee stated: “Businesses are paying to be there and don’t want to waste their money.”

What businesses pay for are keywords: When a searcher types in a search word or words that are relevant to the company’s product or service, its site will appear prominently on the search results page. Search sites sell keywords through real-time auctions. Businesses can buy this advertising themselves. Search engine marketing firms help with the process by identifying keywords to bid on and then by testing the results.

I’m an oddball, it seems, in neglecting paid listings. According to Lee, “All the studies indicate that consumers pay attention to paid search.” He recognizes, though, that some consumers pay more attention than others.

Interestingly, with Google, consumers don’t pay as much attention to paid links on the right of the page as they do to the ones at the top of the page, where they’re blended in more with unpaid results. Consequently, when auctioned, keywords that appear at the top go for more.

Along with offering “paid placement” like Google, Yahoo! also offers advertisers a controversial option called “paid inclusion.” Here, you pay not to be listed separately from the non-paid listings, but to ensure that you’re considered for the non-paid listings. These listings appear the same as listings from sites that don’t pay.

When Yahoo! announced this option, it said that paid inclusion ensures that these sites will be indexed more frequently and that they will be able to submit more information for Yahoo! to include.

All of this points again to the delicate balancing act between editorial material and advertising material.