What are some alternatives?
When comparing SoundCloud and Serendipity by Spotify, you can also consider the following products
Last.fm - The world's largest online music service. Listen online, find out more about your favourite artists, and get music recommendations, only at Last.fm
Pandora - Pandora Radio is a free (ad-supported) internet radio founded in 2000.
Google Play Music - Free radio for everything you do. Store 50,000 tracks from your personal collection. Subscribe for on-demand access to 40 million songs and offline listening.
Deezer - Deezer is a music streaming app created in France. It is available in 180 counties and gets 16 million users a month. 6 million of the users have paid subscriptions. Read more about Deezer.
Bandcamp - Discover amazing music and directly support the artists who make it.
iTunes - Media player, media library, Internet radio broadcaster, and iPhone device management application