AudioGalaxy (circa 1998-2002; precursor to: BitTorrent and torrent sites)
Napster, Kazaa, Grokster -- these are just a few P2P services that rose up, offered free distribution of music, then got sued out of existence by the record labels.
But AudioGalaxy, which began as an FTP search engine in 1998, offered a different approach to file-sharing -- it provided a community, an edited front-end that promoted featured bands, and operated on a pseudo-centralised network that used a Web-based interface and a desktop application to facilitate music discovery and downloading.
For anyone using LimeWire these days, AudioGalaxy may be completely new to you, but it was one of many services that sprang up to replace Napster shortly after the Millennium. It, too, was ultimately sued out of existence.
It's important not to forget AudioGalaxy, though, as it was one of the most innovative P2P applications in history, and a huge number of people loved the service. Although the protocol and delivery method is very different, BitTorrent is loosely comparable to AudioGalaxy in that communities can be built around available files, and editors and users can promote and discover music by looking at what other people have suggested you check out.
AudioGalaxy shut its doors for good in 2002.