How would McLuhan view twenty-first-century society's treatment of the internet?
Marshall McLuhan is an author and media theorist. One of his major theories states that human history could be divided into four eras. Those four eras are the acoustic age, the literary age, the print age, and the electronic age. At the time (1962), McLuhan predicted that the world was entering the fourth age. A staple of this age would be that people would be brought together on a global scale through technology. He called it the "global village," and this concept is what we know today as the Internet. Another aspect of the electronic age would be that the method of communication would be more influential than the information itself. He phrased this concept by saying that "the medium is the message."
We can't be sure of exactly how McLuhan would feel about the current Internet and how people are treating it. I think in many ways, McLuhan would feel affirmed in his predictions. I believe that many of them came true. The world is connected in ways that were impossible only a few decades ago. Information is readily available across the world, and people are capable of near instantaneous communication with huge numbers of people spread across the surface of the planet. I also feel that the method of communication has become hugely important to people, and that is why services like Facebook, Twitter, Instagram, Snapchat, Pinterest, etc. are so popular. They each have found a niche in the method of communication that seeks to gain users.
I also don't think that McLuhan would sit around saying "I told you so" for very long (if at all). He was a forward thinking media theorist. He predicted what was coming based on what had already happened and based on where he saw the current technology moving. If McLuhan was still alive today, I think he would be theorizing and predicting where media would be going in the next one hundred years or so.