YORK, Pa. (AdAge.com) -- If a consumer types a brand name into the Google search box, a home-page link should -- and likely will -- appear as one of the top listings.

But does the same thing happen when typing in a generic keyword relevant to that business? Say, "home repair" for Home Depot or "gifts" for Harry & David? That depends on how well they're optimized for Google. And in the case of those two examples, Home Depot and Harry & David website links don't even make it to the first page of Google, according to a recent study by Covario that evaluated the search-engine optimization health of 100 branded websites.

There are many reasons why a brand might not appear high on Google search. It could be that too many companies are vying to optimize the same keyword, or that a competitor's linking strategy is more robust, or that the brands simply aren't buying keyword ads. Covario tested for what it determined were three key indicators of search health: content usage, link strategy and technical construction.

"Take the keywords 'life insurance,' for instance. Nos. 1, 2, 3 and 4 spots on Google can be worth an extra $50 million to $100 million per year," said Craig MacDonald, Covario's chief marketng officer and author of the study. "There are about eight big companies vying for those spots and each one has an interest in getting good at the word 'life insurance.' And they're constantly defending that position."

Mr. MacDonald dug deeper into his research, and analyzed five brands at Advertising Age's request, to find out why they aren't ranking at the top of Google search.

The do-it-yourselfer destination did not make the front page of Google on the keyword search for "home repair." Lowe's, BobVila.com and even This Old House did, but Home Depot came in on page two at No. 16. It did even worse on two other selected category-defining words: "appliances" and "tools," where it came in at No. 25 and No. 21 respectively. Why?

Home Depot's key problem is that it is missing category-defining keywords in the urls. Mr. MacDonald cited this example of the url for "home repair."

"Even Google got tired of looking at this," he said. "The point is to tell Google what the page is about. I'm not a home builder, but this doesn't sound like a solution for fixing my plumbing."

The good news is that Tiffany did make it to the front page of Google for the keyword "jewelry," but it ranked way back at 29th and 30th for "wedding rings" and "birthday gifts." And even its high score of No. 4 for "jewelry" was bested by, well, Overstock.com.

Another content problem for Tiffany was that for the terms that were found, consumers who click on the Google search link are sent to a country selector page, not a landing page or even a generic home page. On the second click, web searchers get to generic home page, but then must re-navigate there to find the keyword content they initially typed on Google.

"I am already three clicks in and I haven't found what I am looking for," Mr. MacDonald said. Like Home Depot, Tiffany also failed to put keywords in its url.

How could Harry & David not hit the first Google results page for "gifts"? It ranked 17th, with even the New York Times website ranked above it. However, in this case, unlike the previous brands whose fatal flaw was not using keywords in their urls, Harry & David use "gifts" in urls all over its website, Mr. MacDonald said, including harryanddavid.com/gifts on its home page. Harry & David's problem is not content, but the sheer number of links out, one of the other three factors Covario used to determine search health. In the gift segment, linking is extremely important and Harry & David's linking is not nearly as robust or extensive as its competitors.

Finally, one of our chosen brands got a first-place spot on the Google home page. In this case, for the keyword "flowers," not surprisingly since the keyword is part of 1-800-Flowers' name.

Another example: creditcards.com ranks extremely well on credit-card related keywords, better than major card issuers like Bank of America and Citibank, and its the main reason 1-800-flowers does much better than FTD on flower-related keywords.

However, 1-800-Flowers runs into problems with category-defining keywords. For "gifts," they ranked 25th; 13th for "Valentine's Day gifts," and 12th for "Mother's Day."

Again, linking seems to be the cause. 1-800-Flowers uses a dynamic template which is useful to consumers in that it retrieves information on each request, but commonly results in a thinner linking strategy when completely generic keywords are used.

CDW is a business-to-business computer and tech supplier with low consumer awareness, making it even more important for their brand to be included higher up in Google search results. Covario tested it on "computers," "laptops," and "wifi systems." It was No. 18 for computers, but fell beyond the third page for both other category keywords. Several others, including Dell, Hewlett-Packard, Lenovo, and even CNET, had multiple listings ranking above CDW.

Like the "life insurance" keyword problem, the search terms in CDW's space have lots of competition. CDW does buy some keywords, Mr. MacDonald said, but it seems to be leaving the generic terms where people are doing initial research to the big-name brand advertisers, and instead focus on very specific terms where conversion rates are higher.