The search engines are more different than people think

Conventional wisdom is that the search engines serve up very similar results. Our research suggests the opposite: that search engines are far more different than most people think. For example, what do you suppose is the overlap between the top 10 results on Google and the top 10 results on Yahoo! for the average search term? Most people we asked thought about 70 percent. So did we, until we checked.

The actual overlap is roughly half of that. In a test we conducted using the 500 most popular search terms in April 2004, on average, only 3.5 of Google's top 10 results were in Yahoo!'s top 10, and vice versa.

Even more striking is the distribution of results: fully 30% of the search terms had 2 overlapping terms or fewer, and only 17% of the search terms had 6 or more overlapping results among the top 10.

Source: jux2 Analysis of 500 top search terms, April 2004

This is not isolated to only Google and Yahoo! The same goes for Inktomi, presently used by Microsoft, and Ask Jeeves / Teoma.

We are focusing here only on the top 10 search results because we have found that most searchers either find what they are looking for in the first page of results, or they change their query and try again.

However, looking past the top 10 results confirms the idea that the search engines are quite different from one another. In a separate test of 91 random searches, we found that Google and Yahoo! share only 23% of their top 100 results. Furthermore, only 4.8 of Google's top 10 results even made Yahoo!'s top 100 (conversely, only 5.4 of Yahoo!'s top 10 made Google's top 100)