Yahoo and Microsoft are the second and third. According to most major sources, including HitWise, Google has upwards of a 70% search market share. In theory, it means that 7 out of 10 of your potential clients who are seeking DUI help through search go through Google. In reality, it may be even higher than that, given that people often search multiple sources.

Behind Google is Yahoo, at around 14% of the market, and Microsoft’s Bing at around 10%. If those numbers are correct, that leaves around 5-6% of the remaining market to other sources, the biggest of which is thought to be Ask.

While it appears that Yahoo’s search market share is on the decline, Bing appears to be heading up. Given that Yahoo and Bing are merging their search business, their piece of the pie looks to be between 20 and 30% in the next year or two. And given the vast amounts of money that Microsoft is spending to compete in search, it would not surprise most people if that share goes up.

So when it comes to evaluating where you website is, and where it needs to go, the first thought should always be about Google. Google’s search product is the best out there, and if you optimize for Google, you are probably doing a pretty good job for the other search engines too. But don’t forget to check Bing and Yahoo and know what your competition is doing there, and to discover the strengths and weaknesses in your overall online strategy.