Long Tail
Long tail is a statistical term that references the tail end of a lazy J demand curve.
In SEO it is being used to promote the creation of a lot of new content on a daily basis on the claim that collectively total hits to your site would more than make up for your lack of doing well on the important keywords for your chosen topic.
Long Tail Keywords
Refers to choosing to target non-competitive keyword phrases on your website, rather than the more competitive single word keywords. This concept is totally fallacious since all targeted keywords are phrases that consist of two or three different words.
Long Tail Searches
Are about using keyword phrases on your site in order to target very specific audiences. The more specific the keyword phrase that are being used, correspondingly the fewer the number of people that will be interested in your targeted keyword. Why? Because that is the definition of targeting your audience. This is nothing but basic common sense.
Search engine optimization requires the use of targeted keyword phrases. Ego SEOs who yack about long tail searches are just trying to confuse you with their double-talk.