Professor Tom Wilson writes:
"Old news now - two days old - that Yahoo! has dropped Google as its search engine in favour of its own search engine, provided by Inktomi . So I wondered how it compared. I searched for "Information Research" using both and, surprise, links to the journal were 1st and 2nd in Yahoo! Search and also in Google. Not much difference there. So, I searched for "case-based reasoning" at ".edu" sites. In the first 20 links for each search engine, only five institutions were duplicated, and from these five institutions only four Web pages were duplicated. It would seem, then, that the two engines are doing different things and that, if you want a reasonably comprehensive coverage of a topic, it would be a good idea to use both."