The topic of long tail search engine optimization is elusive at best. The fact is, when considering keyword research and acquisition you have the choice of targeting the appropriate keywords that deliver relevant traffic that converts to your website.
The concept of the long tail was originally coined by Chris Anderson editor in chief of Wired Magazine in 2004. The basis is that typical keyword research only scratches the surface and focuses on competitive keywords with one or two words to describe a desired target, whereas most consumers search queries contain 4 or more words containing additional qualifiers and modifiers to zero in on a specific item (depending how far along in the sales cycle they are).
Someone searching for information for a research paper may use a very generic or broad match phrase to find information, however statistically the more specific a search becomes, the less competitive it tends to be as each additional keyword (modifier) takes the competition for that specific “exact match phrase” to manageable and attainable levels.
Instead of dedicating months of SEO resources to acquire an extremely competitive keyword, the logic of long tail search engine optimization is to target all of the offshoots and low hanging fruit that exist to gain a robust presence across a broad range of semantic phrases.