It seems to me that google is threatening to become a clone of 1999 altavista. More and more i'm seeing the top 20 odd searches domainated by a handful of sites, particularly if there is a local placename element to the search.
A quick example is "whats on in ..."
Search that for a major US city provides 4 different sites in the top 23 results, and 1 site for the first 7!
I'm not a google hater at all, but if anything is going to drive people to bing it's this.