Several months after the alliance of Microsoft and Yahoo, Marin Software set out to determine the impact of the transition with respect to search marketing. The findings of the firm’s report, Why the Search Alliance is Paying Off for Paid Search, indicates that marketers should start advertising with and optimizing for Bing.

Marin analyzed campaigns run by more than 800 U.S. internet advertisers, and the company concludes that Bing is gaining significant ground on Google in the paid search market. Since Yahoo and Microsoft joined forces, its advertisers have seen more relevant traffic, as indicated by 12 percent growth in conversion.

As conversion rates have risen, the average Bing/Yahoo cost-per-click has dropped by 20 percent – so marketers are paying less for better leads. Bing/Yahoo’s shares of impressions and clicks have increased to 23 percent and 21 percent of the paid search market, respectively.

In addition to gaining ground in paid search, Marin asserts that the number Bing users is growing, and this could affect the organic search market. The number of overall searches conducted on Bing since the alliance has increased by 7.27 percent. Over the same period, Google’s share of search volume increased by just 0.61 percent. This may be an indication that consumers are increasingly adopting Bing as a search portal, which means marketers will want to optimize their sites for the growing number of Microsoft searchers.

Marin’s assertion that Bing is gaining ground in the search market is supported by Hitwise data, which reveals that Bing searches rose 21 percent at the start of 2011. As Brafton reported, Bing-powered searches represented 27.44 percent of all queries in January. While marketers shouldn't neglect the growing Bing audience, Google is still the search leader, accounting for 67.95 percent of queries.