This graph is an example of the long tail theory, by Chris Anderson.
The green area of this graph shows mainstream product popularity when first released, and the yellow area shows the product popularity lowering after time.
The Long Tail theroy is that the general profit outcome of mainstream products is equal to that of niche products in the long run. An example of this is a mainstream product; Britney Spears' album '...Baby One More Time' (released 1999) which has sold 26 million copies world wide and a niche product; Nirvana's album 'Nevermind' (released 1991) which has also sold 26 million copies world wide.
