You will be able to pick individual windows, and send keys to that window only like "up" to notepad. If you wanted to send "hello world!" to frodo, you could.
There will also be premade commands like pausing winamp or frodoplayer. That way every person doesn't have to make custom window commands for the same program.
so in recap...
built in support for winamp, frodo, and RR.
ability to communicate with individual programs without sending global keypreses.