Only 1.1% of Web search results appear in all top 4 search engines
When the researchers from the University of Pittsburgh and Pennsylvania State University ran 12,570 different queries through search engines at Yahoo!, Google, MSN and Ask Jeeves, they found that only 1.1% of the results appeared on all 4 engines, while 84.9% of the top results were unique to one engine. Only 2.6% of the results were shared by 3 search providers, and 11.4% were delivered by 2 search engines. Google had the lowest percentage of unique results, at 66.4%. Yahoo! had the highest percentage of unique results at 71.2%.