it stands for YouTube Friends consisting of Ryan Higa (nigahigha) Kevjumba D-Trix JR Aquinao Victor kim and Chester see! All friends who are Asain (with the exception of Chester) that create wonderfully hilarious youtube videos and songs together and travel around the world to do ISA shows ISA stands for International Secret Agents! C:
Check out WongFu productions as they are also affiliated with YTF
Boy: Oh man i cant wait to go to that YTF ISA concert in seattle tonight!
Girl: OMG your so lucky i wish i could go!