The most important number is search advertising revenue. The entire online services division (which includes Bing) has revenues of around $2 billion per year.

The most important number is search advertising revenue. The entire online services division (which includes Bing) has revenues of around $2 billion per year. Google's AdWords brings in about $15 billion per year. Microsoft is nowhere close to 30% of the search market, revenue wise. For individual ad clicks Microsoft gets about as much as Google, so clearly Microsoft is not doing 30% of "real" searches (actual people looking for actual things and occasionally clicking on an ad.)