Understanding the Long Tail of the Keyword Demand Curve
It is wonderful to deal with keywords that have 5,000 searches per day, or even 500 searches per day, but in reality these “popular” search terms may actually comprise less than 30% of the overall searches performed on the Web. The remaining 70% lie in what’s commonly called the “long tail” of search (as published at http://www.seomoz.org/blog/rewriting-the-beginners-guide-part-v-keyword-research); see Figure 5-1. The tail contains hundreds of millions of unique searches that might be conducted only a few times in any given day, or even only once ever, but when assessed in aggregate they comprise the majority of the world’s demand for information through search engines.
Figure 5-1. Long tail of search