NBC Television Programming
When RCA introduced their television sets at the 1939 Worlds Fair, NBC began regularly scheduled television broadcasting. The schedule consisted of about 2 hours of broadcasting in the afternoon, and an hour or so in the evening. Much of the programming was done using remote pickup equipment. Sports events, plays, and other events were covered. Even in 1939, NBC conducted audience surveys to help determine their programming. The first television commercial was broadcast by NBC in 1941.
From Radio & Television, April 1940