Peer-to-peer file sharing. There was a time when Napster, Kazaa, eMule were king. The content industry fought against it, but developers came up with decentralized solutions like DHTs or supernodes. I was convinced the next step would be friend-of-a-friend sharing. You only share files with your direct friends. But they can pass on these files automatically, so their friends can get the files, too. The friends of you…
Back in the day of mytunes on a school network, I had HDs full of mp3s. I actively browsed friends (and complete strangers) libraries to find new things, complete an artists discography... etc.
Now? Spotify Premium is probably the best value/$ of any purchase I make in a month.
Even if I wanted to go back to my old ways... its just not there any more. I believe iTunes patched out the features that made mytunes possible, and people don't have computers full of mp3s discoverable on a network anymore.