Facebook Familiar 

Someone you see at a bar or a club who looks really familiar but you can't quite remember how you know them or where from. As the night progresses you realize you may be friends with them on facebook or have just seen them in pictures on facebook because you are that creepy person who looks at everyone's photos and profiles.

"Dude that girl looks really familiar but I can't remember where I know her from."

"Are you sure?"

"Yeah, shes probably just Facebook Familiar"

Facebook Familiar by The Real Reid Durost May 15, 2008

Facebook Familiarity 

When you think you know someone, but then you realise you've just seen them on Facebook... sometimes via a friend or sometimes via Facebook Stalking.

Guy 1 "I'm sure I know that girl..."

Guy 2 "I think she's just Facebook Familiar"

...

Guy 1 "I said 'Hey' to this girl the other day, I was sure I knew her from somewhere... but she disagreed"

Guy 2 "Facebook Familiarity - It's a bitch"

Facebook Familiarity by CommonMistake April 2, 2011