Could you please post this article to Wikipedia? As written, it is a definitive definition of the shag carpet of the late 60s. Thank you.
As an aside, anyone who had this in their home will know that you will never walk barefoot again - anywhere. If you ever had a real Xmas tree in a home with shag carpet, just know that ornament hooks and dead pine needles are your present and, wait for it, your future. (!)