title: What is the difference between NSNotificationCenter and the Key Value Observing technique?
body: <p>I just read a couple of tutorials regarding KVO, but I have not yet discovered the reason of its existence. Isn't NSNotificationCenter an easier way to observe objects?</p>
  
  <p>I am new to Stackoverflow, so just tell me if there is something wrong in the way I am asking this question!</p>