Google has bested Yahoo! and Microsoft in revenue earned per share in the second quarter of 2007, according to the white paper “Market Share Trends within the Engines, and Their Impact on Brand Marketers,” from SearchIgnite and RBC Capital Markets.

This report revealed that Google has a 76 percent market share, regardless of only 60 percent of ad impressions. Because of Google's continual tweaking of quality score algorithms and minimum bid requirements, its revenue per search keeps on growing. On the other hand, Yahoo! had 34 percent of searches among its network even though it held 18.3 percent of media spend in the second quarter this year.

Search engine market share is defined as the percentage of media spend. It has stabilised this year, since Google, Yahoo! and Microsoft could not make significant gains.

This study was conducted from January 2006 through June 2007, tracking more than 14 billion impressions and 185 million clicks on Google, Yahoo! and MSN across over 500 marketers.