Bill Tancer has a graph (which excludes YouTube) on the Hitwise blog:
Currently, when we look at our US sample, visits to the top twenty Yahoo! properties are more than double the top twenty Google properties (I've excluded YouTube from this analysis). Over the last year (November 19, 2005 to November 18, 2006), Yahoo's market share declined 10% while Google gained 18.6%. If we apply those growth rates, and assume no material changes in those rates over the next three years (a big assumption), Google would not surpass Yahoo! in market share of visits until mid-2009.
Somewhat more interesting are the tables showing which properties have the most visitors. It seems that a third of Yahoo's traffic is to its email service, and search shows up quite well. With Google, almost 79% of the traffic is to the Google search page and 9% to Image Search. So 15 of Google's top 20 properties get less than 1% each, with Base attracting only 0.04%.
It's hard to compete with Google, even if you are Google....
