Anyone in business is familiar with some iteration of the 80/20 rule: 20% of people account for 80% of the work. This type of breakdown is common in a variety of forms and is a good rule of thumb.
This breakdown has become real in the search world. Google now accounts for 80% of all search volume. The remaining 20% is Yahoo, Bing, AOL and a few niche engines.
Yahoo has lost users, but they have gone to Google and not Bing (despite the $100,000,000 advertising launch).
Bottom line: if you want to capture 80% of your audience, you need to ensure you have a presence on Google.
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