The Airport Express public key was previously known, which allowed anyone to write a program to stream audio to an Apple Airport Express. Now that the private key is known, anyone can write a program to receive audio from iTunes, or from another program that sends to Airport Express.
This means you will be able to easily send audio to other rooms in your house with something like XBMC running on a PC, nettop, or netbook.
edit: Just to clarify - previously you could do this:
iTunes -- stream to --> Apple Airport Express
3rd party software -- stream to --> Apple Airport Express
Now you can do this:
iTunes -- stream to --> 3rd party software/hardware
This means you will be able to easily send audio to other rooms in your house with something like XBMC running on a PC, nettop, or netbook.
edit: Just to clarify - previously you could do this:
iTunes -- stream to --> Apple Airport Express
3rd party software -- stream to --> Apple Airport Express
Now you can do this:
iTunes -- stream to --> 3rd party software/hardware