Facebook Home, unveiled today, is the company's attempt to stop what it sees as an alarming trend:
Facebook users actually spending less time on Facebook.
So what is Facebook Home? To quote the video below:
“Home isn’t a phone or operating system, and it’s more than just an app. Home is a new experience that lets you see the world through people, not apps.”
Basically, it's a suite of apps that constitute an interface for Android users willing to let FB mediate pretty much everything they do on their mobile devices.