There's not much dispute over Google's dominance in the search engine wars, but there has been a lot of conflicting data regarding just how dominant Google is. Andrew Goodman wrote a nice article on Clickz about the subject of search engine popularity. His article is a summary of the Search Landscape panel at the Search Engine Strategies conference a couple months back.
One interesting "nugget":
Tancer offered a surprising nugget about the emerging category of desktop search: it is popular with older users. He made the audience laugh with an anecdote about his mother. Finding out that she and many of her friends were early adopters and frequent users of desktop search, he had to know why. "Because older people lose things, dear," she replied.
Read the article