Don Draper is not who he says he is. The same could be said for his colleagues and their spouses. There's a lot more to the story plot than meets the eye. What people like most about the characters in Mad Men is that they may be cads (male and female), but they're not a bunch of pussies. The audience loves the fact that these non-pussies are so ruthlessly acting in their own self interest, it seems refreshing. [See the rest of this thread at Fast Company Expert blog.]
That is counter to the spirit and increasingly the reality of our times. The name of the game now is collaboration. Companies are finally replacing the metaphor of business as a family, which it never was, with that of business as teams - as in team work for performance.
Rather than seeing the world as flat, I'd say we've come full circle - back to tribes, and to trust. We all know that the characters of Mad Men cannot continue their deception, mostly because they each know, deep down, that even when they're found, even when it doesn't matter to others, it matters to them.