Mystery Science Theater 3000 (MST3K) is one of those holdovers from early cable. Back in the day, most cable channels were like small market TV stations, with limited budgets that didn't allow for the production of fancy shows. Therefore, they did what small TV stations had always done, they showed old movies.
MST3K's hook, however, was that they placed three characters down front (at the bottom of the screen) and allowed them to talk over the movie's soundtrack. Not loudly enough to ruin the movie, but loudly enough that the viewer could follow either the movie or the conversation. The remarks were a little like the class clown in Junior High who felt compelled to comment on everything that went on around him. It was pretty funny, really.
Early shows were pretty good and the novelty factor was high. Later shows selected worse and worse movies to lampoon and began to get longer and more elaborate scenes between movie acts. That's about where I stopped watching.
Shows like this can still have a place on TV today and I think MST3K was good campy fun, but I think it should have kept the intro scenes short and sweet. I give it 4 and think the producers would be proud to know they really earned it.