Interesting viewpoint. Does the author really follow this? Has a webpage, blog and an archive that stretches for 91 pages ~ http://calnewport.com/blog/archive/ Not a good sign if the author thinks you should quit or limit your social media contact. I don't care if the authour justifies this as necessary. It's a sign that ignoring the real problem doesn't seem to work.
The Internet is addictive. In fact I've spent a bit of time writing my own tasking system to tackle this problem. In writing up an accompanying blog post on distraction and focus I found the GTD, work hard, achieve more in less time frenzy isn't new. It pre-dates the Internet by decades. Take Charles R. Schwab, owner of Bethlehem steel, someone who Thomas Edison described as a hustler. Schwa hired the best productivity guru he could. Ivy Ledbetter Lee. Lee proposed a very simple technique to focus and work on. Then charged Schwab USD$20,000 for the effort. You can read more in this article, "Ivy Ledbetter Lee" ~ http://jamesclear.com/ivy-lee
Quitting social media is a temporary fix as you'll probably find other ways to distract yourself and avoid work. The deeper problem is realising the Internet is very addictive and find coping mechanisms to counter the side effects.
While reading up on the problem of Internet addiction and digital works, I re-read the article pg wrote on this topic, "Distracting Distractions" I found an update on his suggestions: "The strategy described at the end of this essay didn't work. It would work for a while, and then I'd gradually find myself using the Internet on my work computer."
It is a problem that could yield some interesting work.