The separation of structure, presentation and behavior is dead
http://blog.teamtreehouse.com/the-separation-of-structure-presentation-and-behavior-is-dead
Separation of semantic and presentational markup, to the extent possible, is architecturally sound
http://www.w3.org/2001/tag/doc/contentPresentation-26.html
Separation of presentation and content
http://en.wikipedia.org/wiki/Separation_of_presentation_and_content