Spotify is a software that allows users to stream music from a vast collection of labels. The service allows users to "sign-in" through Facebook or by creating a personal username, follow their friends, share what they are listening to, see what others listen to, share playlists, discover new music based on taste, etc. Because of the streaming nature of the service, no actual music files are downloaded or stored, but Spotify allows users to favorite songs that they can then access them later. Favoriting and streaming maintain the personalization of music libraries (i.e. each user has his own library and playlists) without providing actual ownership of that music.
The free version of Spotify consists of unlimited computer access to any music on the service (with the interruption of ads) while the paid version allows access to music on mobile devices in addition to computers and without ads interspersed with the music.
The program has essentially changed the way people listen to and share music. Instead of owning a disk or having a library of downloaded music, users stream what they listen to through Spotify. Friends can create playlists and send them directly to each other, where they can immediately be listened to without any downloads. Users also have the option to make what they listen to available to be seen by friends and, in turn, see music listened to by others. This system gives its users more immediate, refreshed information and allow them to discover what others like while on their own computers. In a sense, you can "peek in" on what someone is listening to simply by clicking on what Spotify tells you that person is playing at the moment. Likewise, Spotify recommends new music and playlists based on your music preferences shown by what you have been playing. Popular playlists that appeal to individual music tastes, for example, will show up on the user's "Discover" page as something he might be interested in.