Google v. Yahoo! Predicting the Intercept

I came across Ben Charny's article that cited Citigroup's (Mark Mahaney) prediction that Google would overtake Yahoo! to be the top Internet property some time in 2007. I decided to pull the chart below on market share of visits to the top twenty properties for both Google and Yahoo! to see what insight our data might provide on a potential intercept.

Currently, when we look at our U.S. 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.
Finally, by popular request, the table below indicates the percent market share for each domain or sub-domain relative to the top 20 properties for both Google and Yahoo!. As the table indicates below one of Yahoo's advantages is the distribution of its visits over several properties, where Google has over 87% of its top 20 visits in home page and image search visits.