Apart from the internet itself I think digital content distribution is revolutionary, it certainly has drastically changes the way we acquire games, books, music, movies etc.
It's changed the content that an average person has access to without replying on what as being distributed locally. It has allowed those that would have never been able to get wider distribution of their content, those producing niche material to access a big enough market to make their projects viable.
So it may not have changed the content on the whole but it has certainly changed the content that most people are actually able to experience.
Ability to experience mayn't align with actual experience; while radio could've increased music diversity, it's effect seemed ultimately homogenizing, and the same may be true of online content.
