As you're learning about search marketing and SEO, you will definitely run into the phrase "the long tail". Let's turn this odd term into a familiar one by looking into long tail keywords. What are Long Tail Keywords? When you are identifying keywords for your internet marketing (both SEO and PPC), the metric used most to compare keywords is its popularity. If you put all the keywords that "exist" into a graph, it would look something like this (see story for chart).