Facebook Unicorn
A Facebook Unicorn is someone you barely know, but you're still friends with on Facebook. They might be someone you had a crush on, someone you met at a bar, or someone who added you because they thought you were cool.
Hey. We had that one crush on each other in high school. I still think you're cute.
Oh my God. You're that guy from the bar. Why are you still friends with me?
You're the one who added me at 3 AM. I still don't know why.