[Update: I've consolidated all of my TV anachronisms posts at a different blog, Prochronism, and new ones on Mad Men, Deadwood, Downton Abbey, and the rest are going there.]
I've got an article up today on the Atlantic's web site about how Mad Men stacks up against historical language usage. So if you're reading this blog, go read that.
Maybe I'll add some breakouts of individual episodes later today if I get some time, but here are the overall word clouds like the ones I made for Downton Abbey. Mad Men has noticeably fewer outliers towards the top:
And the ones that are are actually appropriate. (My dissertation actually has a bit on the origins of focus groups in the 1940s).