fb is an acronym for the term “free base” meaning you have a place for you and your friends to hang out. for example, your house is empty and you want people to come.
John: “Hey Mark. Do you want to link, I have an FB.”
Mark: “Sounds good, see you there”
(STAN TWITTER)
follow back. used when asking someone to follow you back on twitter
person one: fb please!
persons two: done! *follows back*