When you are talking to a friend on the computer and you both run out of things to say. If you say TBT you are excused and dont have to say anything until you think of something interesting to talk about, provided the other person says TBT back.
Magi: Yea... TBT?
(20 min later)
Magi: Guess what? I got a new dog :D
Gio: Noway! Thats so cool :P
#tbt me as a cute 5 year old
#tbt corded phones
Referenced from the once great singer/song writer Cher, Carl Lindquist has since popularized the famous saying "turn back time" into a abbreviated power house in the social media world.
Bitch, I swear to god! If I could TBT I would have slapped your momma!!