BTT simply means 'back to the top' and is an acknowledgment of a good comment by another Freeper. It is not a vanity post so I don't know what the heck you're talking about.
Oh.
Thank you.
Thought it meant: Back to the top, fellow FReeper—You’ve lost the plot!
Likening it to a director or conductor who feels the need to stop the music and say “Back to the Top” to a band or orchestra that has gone out if sync with each other.