According to Nielsen//Netratings Google is the leader among search engines, but users have started using other major engines also. A new research (opens .pdf) only a small number of users use only one search engines. Nielsen//Netrating explains that 58 percent of Google searchers also visited at least one of the other top two search engines, MSN Search and Yahoo! Search, showing that even though Google’s market share is dominant today, there is significant opportunity for its competitors to grow.