Sent to you by moya via Google Reader:
Facebook now has "places" - it "checks you in" when you go somewhere. This means home too. It goes out and grabs the location from Google Maps. It is turned on by default, and Facebook isn't making an effort to let its users know about this when they login.
It's up to you, but I really recommend you disable it. The last thing anyone needs is for people to know where you live, when you're there — and when you're not.
Seriously, fuck Facebook. Facebook is profoundly evil.