Files are shared through Gnutella networks. That means you'll access millions of music files that can be downloaded at top speed. Furthermore, you can import your own mp3 files or iTunes library to use it as music central.
The second part of All is its social component that grants you the possibility to know new songs and people.
You can change settings of that social network to share files and likes with family, friends or everybody.
All is a really good application that guarantees new songs everyday, perfect for music lovers.