Who's index is bigger? And who returns more results? The following comparison would still lead me to believe that Google is still number 1.
NCSA Compares Google and Yahoo Index Numbers: "chrisd (former Slashdot editor and now Google employee) writes 'Recently, Yahoo claimed an increase of index size to 'over 20 billion items', compared to Google's 8.16 billion pages. Now, researchers at NCSA have done their own, independent, comparison of the two engines. '"
(Via Slashdot.)