According to MacRumors developer James Laird was able to reverse engineer the Airport Express key and posted an open source emulator he named Shareport. It is an open-sourced AirPort Express emulator that contains an RAOP server to stream music from iTunes and iPods to third-party software and hardware.
One report says that before it was only possible for users to stream from iTunes or licensed third-party software/hardware to AirPort Express. Now users can do it the other way around, that is stream iTunes to third-party party software or hardware.
This could make it possible to stream content easily between devices around the home that typically wouldn’t be capable of such things. As MacRumors puts it, this could mean other Macs, modified consoles or other mobile devices with an application designed for this.