Previously Apple iOS customers would have to stream music through Sonos' dedicated application. With the new update, it'll be easier for iOS customers to take advantage of a Sonos system.
Sonos systems create their own network to play music. Their speakers latch onto the network and fill various rooms with synchronised sounds, irrespective of whatever else is using your home broadband.
They also have the distinction of being a networking speaker capable of playing a different song for each room.