From Robin Good's insight:
"OnePlaylist.fm is a new web app which allows you to search YouTube videos and the full Spotify catalog for music tracks and video clips and to collect your preferred ones into shareable playists.
You can also import existing playlists straight from YouTube and Spotify. Not only. Once you have created a playlist, you can synch it with your account on YouTube, Spotify, Rdio, Deezer and many other music services...."
Read full Robin Good's insight below.
Check out it: http://oneplaylist.fm
Example of a published and public playlist page:
Via Robin Good, Giuseppe Mauriello