For all of you that are not the most geekily inclined, FreeBSD is a Open Source version of Unix that is an ancestor of Mac OSX. What that means is that Sony's Orbis, Mac OSX and Linux share a very similar Unix core. Since they all rely on OpenGL and the like it could mean an easier time for games to be ported across these three platforms.
I know that just because a company brings a game to the PS4 that doesn't mean they care about Linux or MacOS....
More accurately, FreeBSD and Mac OSX share a common ancestor. But that's just being pedantic. :)
This is really awesome, though, especially if they leave it even slightly open for enthusiasts to tinker with it.