McLuhan's Tetrad Of Media In Media

As I have learned from the notes, McLuhan developed his idea about media in a simple concept titled "Tetrad Of Media". This concept included four laws which are enhances, obsoles, retrieves, and reverses.
I choose instant messaging as an example to explain McLuhan's Tetrad Of Media. First, by using instant messaging in our lives, we have enhanced in the terms of voice and words because we can chat with people in the form of words or voices. Second, instant messaging makes signal smoke and letter obsolete because it is faster and easier to use. Third, our sense of communication have retrieved as instant messaging let us communicate with people no matter where they are. The last part which is the reverse part, instant messaging will cause people get into many troubles like disturb by strangers.