Someone who knows everything featured on the internet, in movies, in the music scene, or on TV, and uses it in daily life (and makes it cool not geeky). If you say something remotely close to a line from a movie, they might quote it. Want to know anything about a youtube video you haven't seen yet? Ask the pop cultured guy.
They probably use lol in real life.

Someone who used to be a potential girlfriend/boyfriend, but no longer is.