Comment Re:Only 63% (Score 1) 150
In the US, the big three are Google, Yahoo, and Microsoft (in that order). I think Yahoo is around 20% and Microsoft around 10% (very rough estimates, don't quote me). After that, it's mostly bit players (perhaps with the exception of Ask). I'm not sure what the current numbers are but here is a TechCrunch article from June that has more specific figures:
http://www.techcrunch.com/2008/06/18/comscore-may-search-data-google-yahoo-up-microsoft-slides/
Market share varies a lot by country, though, so don't assume a similar breakdown worldwide.
Market share varies a lot by country, though, so don't assume a similar breakdown worldwide.