As Yahoo CEO Jerry Yang takes the next 100 days to come up with a new strategy for the company, he may be well-advised to keep in mind some of his smaller customers.

A new study shows most small and medium sized advertisers aren’t satisfied with the results they’re getting from buying search keywords on Yahoo.

The study of more than 1,000 advertisers, conducted by Outsell Inc, found that less than a third of the small and medium sized companies rated Yahoo’s search as “effective.” By comparison, 58 percent of those same companies found Google’s search to be “effective.”

That’s only more bad new for Yahoo. The study comes out a day after the company reported lower quarterly profit and cut its revenue expectations for the year.

The silver lining, if there is one in the study, is that large companies appear equally satisfied with Yahoo and Google, with just over 60 percent of those respondents rating the two companies’ keyword search service “effective.”

Other findings from Outsell’s survey: 

• “Small companies’ share of online ad spending on search engines is more than double the share of medium or large companies.”
• “Small companies devote almost twice as much of their budgets to print as medium-size companies. However, mid-size businesses rate the effectiveness of print trade magazines and events much higher than smaller companies do.”
• “Click fraud continues to deter some companies from pay-per-click advertising. Large companies estimate that nearly one-fifth of clicks on their ads are fraudulent, compared to small companies’ estimate of 14.4 percent.”