Last Sunday's series finale of "Mad Men" set off a firestorm of debate -- did Don create that Coca-Cola ad? What does it mean? Why was it used? -- and creator Matthew Weiner has revealed some answers. Sort of.

Weiner spoke at a New York Public Library event, and of course, questions about the finale popped up. "I have never been clear, and I have always been able to live with ambiguities," he explained of the elliptical ending. But he did make clear that Don created that ad.

Here's an overview of what else he said:

The ad is not meant to be cynical -- rather the opposite: "I did hear rumblings of people talking about the ad being corny. It's a little bit disturbing to me, that cynicism. I'm not saying advertising's not corny, but I'm saying that the people who find that ad corny, they're probably experiencing a lot of life that way, and they're missing out on something. Five years before that, black people and white people couldn't even be in an ad together! And the idea that someone in an enlightened state might have created something that's very pure — yeah, there's soda in there with a good feeling, but that ad to me is the best ad ever made, and it comes from a very good place."

The hug with Leonard is a breakthrough emotional moment: Weiner noted that, in those days, men didn't express their emotions "other than in bar fights." Like many veterans after the war, "Don is just ignoring this stuff, and it keeps bubbling up. And a lot of his, what we would now call self-medication, drunkenness, whatever, womanizing, is to avoid those feelings." So, Don hugging a stranger and crying with him indicates a major turning point. "I hope the audience would feel either that he was embracing a part of himself, or maybe them, and that they were heard. I don't want to put it into words more than that."

Betty's fate was written long ago: "I knew very early on. Her mother had just died in the pilot, and I knew this woman wasn't going to live long, and we love the idea of her realizing her purpose in life right when she ran out of time."

But not Peggy's: "I didn't know Peggy and Stan would end up together -- that had to be proved to me."

The phone was a character unto itself: Some of us felt a little cheated not to see Don interact on screen with Peggy, Betty, or Sally, but Weiner wanted those conservations to happen over the phone. "A lot of the most important things in my life have happened to me over the phone. It's a dramatic situation almost every time when you answer the phone ­-- if you answer the phone."

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