Facebook Graph search allows you to search everyone who uses this app. Be it your friends, people who aren't your friends, just about anyone.
Example criteria:
"Single women I am not friends with who use BangWithFriends"
"My friends who use BangWithFriends"
I ask this because I frequently signup with Facebook on some apps, and purposely put it to "Only me" privacy, to keep my activity hidden from my Facebook friends. I would hope that doing so, would keep me out of those types of Open Graph searches. Can anyone confirm/deny this (I don't have Open Graph Search, yet)?