Search engines are used by 87% of Web users looking for information. And every month the search sites get better at helping users zero in on the desired information. But they are still pretty weak when searching on broad categories such as “loans” or “credit.” There are just too many uses of such terms on the 50 million pages catalogued. All the more reason to consider a banner ad. If you search on “credit cards” and receive 514,000 possible sites, you may not visit a single one. But that 5.9% teaser ad might just draw a quick mouse click.

Search engines provide a unique advertising opportunity, one that doesn’t have a counterpart in other mediums. The ability to “sponsor” keywords or a group of words creates a whole new category of target marketing. (Sponsors pay to display their ad banner each time the keyword is used in a search.)

Financial services companies have been advertising on search engines since the beginning. But as you can see from the chart above, there are still plenty of keywords for sale. We checked the 13 loan terms above on four major search engines, plus Yahoo (which is a directory not a true search engine). Of the 65 possible advertising buys (13 words times 5 Web sites), only 27 (42%) were being used by a financial services company.

The table above shows how many Web sites were listed in the results of each search. Multiple words were enclosed in parenthesis, but not all search engines recognize this convention. So comparisons of the results from one site to the next are more challenging.

The table also lists the financial services companies sponsoring each search term. Sponsorships can change from one minute to the next, so this table represents just one particular slice in time.

We were surprised that many of the search terms were not sponsored. All five sites had a sponsor for “mortgage,” but only Yahoo and AltaVista had a sponsor for “refinance.” Even more surprising, “home equity loan” had just one sponsor, John Hancock on InfoSeek. Below you can see which sites were most popular with financial advertisers