The meaning of FTFY is “fixed that for you”.
It was created sometime during the 90’s on various message boards, forums and chatrooms, where people had been abbreviating every conceivable phrase or expression.
The arrival of SMS technology in our lives didn’t help the matters, as there was a day, when it was an effort to type in a full message on a phone.
“FTFY” can be encountered up to this day, mostly in private chats and text messages.
Husbands tell about the freshly cooked dinner to their wives, who share the news about the plumbing they fixed with these four letters.
Hell, even Bob the Builder is just writing a message to the contractor after having finished the job and left early.