Streaming music startup Serendip began offering its “lean back” music discovery service to mobile devices this week with the debut of the Serendip iOS application. Similar to its Web version, the new app offers a “continuous stream of the music popular among friends, or others you’ve dubbed your ‘music soulmates,”’ explains TechCrunch.

“However, unlike on-demand services like Rdio or Spotify, for example, which also offer this level of social insight, Serendip aggregates music from YouTube, Vimeo, SoundCloud and Bandcamp to create its playlists,” according to the article.

“Serendip is the perfect lean-back experience, just like good ol’ radio,” reads the iTunes description. “No more searching for music or drowning in your music library. Serendip keeps playing, while you enjoy the music, non-stop, hassle-free on your mobile phone. And it’s free!”

Another difference between Serendip and sites that stream music and create radio stations based on artists a user likes, Serendip is out to help you find new music to listen to. The company reports it has a catalog of more than 50 million songs so far.

The service “recommends a few ‘DJs’ upon first launch (there are over 15 million of them!), to help you get going. And as you get more into using the app, you’ll come across others with similar music tastes, and you can then follow their music which becomes a part of your own playlist,” explains TechCrunch.

“Our playlist  is not boring and predictable, because it is curated by people… the ‘curated by humans’ part may resemble turntable.fm or Songza, but it is done on a much larger scale, and at your convenience (you are not dependent on others to use the service at the same time),” says co-founder Sagee Ben-Zedeff. “And we let you control it, and move across your feed so you can freely explore and enjoy the music the way you like.”