Someone please tell Steve it's "who's."
Steve just wanted to make the guyz laugh, and his friends turned it into the most drawn-out knock-knock joke since "Banana Who?" Still, it's nice to see a Facebook joke hijacked for something other than racism. There's a pretty good chance this is staged, since David is David Bussell, a comedian, but we still wish our Facebook friends did this instead of just sharing pictures of their dumb kids.
The joke continues below: