This was considered one of the worst TV shows of all time by some critics though it was a ratings smash. It was also one of the shows Bill Paley killed off as part of the "rural purge" in 1970 and 1971; to make way for more urban shows like The Mary Tyler Moore Show (1970), The Bob Newhart Show (1972) and All in the Family (1971) which were thought to appeal to a richer younger demographic than the Paul Henning Hayseed shows of the sixties (The Beverly Hillbillies (1962), Petticoat Junction (1963), and Green Acres (1965)).
When the other little kids played hide and seek, Little Milby started his first business.
Milburn Drysdale: Every kid had a lemonade stand.
Jane Hathaway: He opened a pawn shop!
The premise of the series, according to the pilot & the theme song, is that "a poor mountaineer" accidentally found oil on his property. But oil deposits do not occur in or near mountains - the geology of a mountain does not sustain oil pockets.
Some of the Public Domain episodes of the show have "The Ballad of Jed Clampett" replaced with a generic theme song for copyright reasons.