The Long Tail Keyword Demand Curve refers to a well know graphic or chart that attempts to explain the keyword relationship between ...

  1. The length of a keyword phrase (how many words make up the keyword phrase).
  2. How many searches there are for that keyword phrase which is a direct indication of potential consumer demand for any products or services related to that long tail keyword phrase.
  3. How much competition there is for the keyword phrase meaning how many peices of content are online (web pages, blog posts, online videos, etc) that are OPTIMIZED for that keyword phrase (keyword phrase is in the pages title, the url or web address of that web page).

The long tail keyword phrase curve charts displays a common rule with keywords that applies MOST of the time and is:

The less number of words that are in a keyword phrase ...