This series is most noted for the introduction of Scrappy-Doo, Scooby's nephew. Some say that this is what killed off the long-running series, but they're wrong; Scrappy actually *saved* the show from oblivion.
By the late 1970s, the run of Scooby-Doo shows was losing steam and needed something to revitalize it; an injection of "Puppy Power" did the trick. Even when the show went through various format changes (which would've happened with or without Scrappy), people kept watching and kept the ratings high because of that precocious pup. Indeed, that was why he stuck around season after season for almost a decade. Had he never come along, Scooby might now be as obscure and forgotten as Goober or Dinky.
"The Scooby and Scrappy-Doo Show" marks the beginning of a long, strong run for Scooby-Doo, and for that reason alone deserves a special place in Hanna-Barbera history.