The ability to quickly spin up a "radio broadcast" in Grooveshark for friends was amazing. With a small group of five friends we set up a Friday DJ rotation where one person would queue songs all day and the others listen in. All the "broadcasts" got saved as playlists, which you could "favourite" from your own account and go back to whenever you wanted. People could make requests when they had a "next track" that would segue well with what you were already playing. It was really fun!
I have never had a period of more high quality music discovery and I sorely miss those playlists, many of which featured obscure/rare/live tracks that simply aren't available in today's music services.
There was a good episode of the podcast Startup about the Grooveshark story. They didn't quite understand how strong the UX was. Too much of the episode's focus was on the exhaustive free library. But it was still cool to hear about it and made the loss sad again.
I brought a premium account, even though I was a student at the time. They had some music tracks that I still haven't found anywhere else. Groveshark introduced me to filk making fun of Scifi I didn't know existed.
Paying for music isn't an issue, but it sucks when copyright is used to control music.
I have google music, and it is good, the music they have is generally of higher quality, but the selection does not compare.
Their "radio" generation from a playlist of relatively few tracks was also out of this world, in contrast to spotifys ““daily"" which only gives me a new list every two years or so.
Despite using the desktop application an hearting the living bejeezus out of it...