It's a shame that recombinantrecords.net has removed that from his site, even though it's original work, because lawyers sued him for using the title of a (good) book "Amusing Ourselves to Death". Then, 9GAG & other sites have no problems copying the content. It just goes to show you that you can't stop information flow. All you can do it stop legitimate players from controlling it.
...but was apparently taken down due at the copyright holders' request. More on the book:
If they left the comic up but clarified what it was inspired by it would definitely help the Postman estate.
The conversion rate of "Do yourself a favour and read Neil Postman's words in full. Purchase a copy of Amusing Ourselves to Death new/used (aff)" must be a rounding error on 0.
(I'm guessing that the subtlety of the comic's original Postman mention – at the very bottom – compared to the top line "AMUSING OURSELVES TO DEATH by Stuart McMillen" may have started the attribution discussion off on the wrong foot.)