4.3 billion searches in the United States during July 2010.

That’s how many searches were handled at Yahoo! and Microsoft controlled sites for the month. Both saw modest gains while Google saw a slight decrease but the biggest message is in comScore’s new “Explicit Core Search Query Report“.

As Yahoo and Microsoft increasingly intertwine their search businesses, the companies combined for nearly 1/3 of all US searches.  And there are studies that suggest certain product categories convert better for sales or leads than a Google search or advertisement.

Your takeaway as a small business leader is that Google remains synonymous with search, but ignoring a combined 33% of the market is bad strategy.  The advertising formats and frameworks are different for Google and the new Microsoft adCenter Search Alliance.  Facebook adds a third, complicating wrinkle, but search advertising is no longer Google and 5 smaller competitors.  There are three platforms with opportunities, and the small business leader will have a stake at all three.