Facebook Familiar
When you think you know someone, but it's just because you've seen them on Facebook. Maybe through a friend, or because you've been looking at their profile like a madman.
I thought I knew this guy from somewhere, but it was just because I saw him on Facebook through my friend.
I said hello to someone at the grocery store, and it turned out I've been following them on Facebook for months.
I thought I recognized this person, but it was just because I saw their Facebook post last week.