This is one those it-writes-itself-jokes news bits. From Pitchforkmedia:
For those of you who might not be familiar with “4’33”: Yes, it is supposed to be completely silent. iTunes offers a helpful explanation on the download page, but I can only imagine how many people are being baffled by it at this very moment.
Hats off to the joker who wrote in the customer reviews, “It’s great that iTunes is offering free John Cage, but they should have really offered the remastered version. The difference is plain to hear!”