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