The digital age’s reversion to pre-literate communication

According to media theorist Marshall McLuhan, every medium is an extension of our physical or mental faculties. The hammer extends our fist, the spear our teeth, the hut our skin, the wheel our feet — and electronic media extend our central nervous system to all of humankind. 
Extended abilities give us new powers but disrupt previous sensory, cognitive, and social settings. As humankind switched to the internet, printing no longer defines the protocols humans live by. Print-based culture is collapsing. 
The era of printing was, in fact, very short by historical standards — about 550 years. Some call this period the Gutenberg Parenthesis — a metaphor popularized by Jeff Jarvis. Within this Parenthesis, communication was centered around fixed, authored, linear, and stable texts. 
Things were different before books. Communication was fluid and situational, passed mostly through direct interaction between people. The internet has largely restored t