As a tribute to the recently canceled I Spy (1965) the star of that series, Robert Culp has a small cameo as the drunken waiter.
The title was inspired by another classic spy series I Spy (1965). Interestingly, that series premiered three days before "Get Smart", and that show's final episode aired two weeks following the airing of this episode.
The name of the third spy network, Attrocities Cruelties and Brutalities (ACB) is a direct reference to ABC (the American Broadcasting Company), which was the number-three network in terms of rankings at the time this was filmed. ABC was also historically the third network formed.