You know how the "next week on Mad Men" promos are always hopelessly, comically vague? Well, there's a perfectly good reason: Matthew Weiner wants them like that! (OK, maybe it's not so much a "perfectly good" reason as it is a "reason.") Speaking with CNN, Weiner explained that he doesn't "even want those scenes from next week ... they could put a promotion for some other AMC show in there if they wanted to." So the network compromises, letting him "weed anything out that I think is a spoiler. And honestly I didn’t know they were going to become a joke." More to the point: "I paid so much money for that song at the end" — up to a quarter mill! — "I want you to sit there and let it wash over you and think about the experience you just had. Let it resonate a little bit, and not say, 'Hey, don't go away.' I am a firm believer that the last 30 seconds of the show is when people decide to come back."
In conclusion: The Mad Men promos are elliptical founts of confusion because Matthew Weiner is an exacting control freak with a very specific vision. Mmm, yep, pretty much what you'd already assumed.