The whole point about 4' 33" is that it's NOT silence. One's meant to be taking in the various unavoidable sounds that would normally just be in the background. Unless you live in an anechoic chamber, there ain't no silence.
The trouble with the works like 4'33" or Malevich's Black Square to me, is that works like this needs an explanation, a detailed history of why you should love it instead of hating it. To me it ruins the whole experience of a true inspiration... like, have you ever seen a man saying "Man, just heard this Mark Nopfler song, what a rubbish! Anybody can came up with something like that, a bunch of Hawaiian noises". I guess not often...
While I perfectly understand the meaning of 4'33", and I understand that Malevich's Black Square was created for a protest about religion, these works doesn't inspire me that much. I'm feeling like I learned a nice piece of trivia, but nothing more. Oh, so there's a sound of a crowd in a concert hall? I never knew about that... I thought musicians always plays in a vacuum of space.
I would be more happy if creations like this was part of some book, film or story, but not a real thing that got sold on iTunes. It's a shame!
P.S. Sorry for an off-topic, but we have nothing to discuss anyway