Last.fm is an online community founded in 2002 focused on music scrobbling and streaming. It can be considered as an ante litteram as it was and is actually incorporating a music scrobbling system that enables to create people’s personal music playlists and share them among the users.
Spotify has a close resemblance with this online community but to me is less complete as it does not give people the chance to share their own opinion as Last.fm.
This online community users have the chance to express an opinion regarding music and suggest other people what to listen to thanks to a comment system.
Moreover this suggestion system is even improved in the website itself as it automatically suggests similar artist to the ones people are listening to enabling to broaden music horizons discovering new singer/bands.
Furthermore, even radio stations from Germany, France and UK were included in this website, giving people the chance to listen to them apart from listening to single track, but unfortunately this service was closed down in 2014 in favour of scrobbling only.
I advise people to give it a try and try to use it, it is really mind opening. Do not stick only to Spotify!