The best thing about Virginia Heffernan's New Yorker profile of Tina Fey, besides feeding our Tina-Fey-starved minds, is the breakdown of the different comedy styles of SNL performers and writers:

Second City (Dan Aykroyd, John Belushi, Bill Murray, Gilda Radner, Rachel Dratch, Amy Poehler, Horatio Sanz) - known for their aesthetic perfectionism
Groundlings (Laraine Newman, Chris Farley, Will Ferrell, Julia Sweeney, Maya Rudolph, Chris Kattan) - creation of vivid and eccentric characters
Harvard Lampoon (Dennis McNicholas, Michael Schur, Conan O’Brien) - emphasis on the conceptual premise of a sketch

Then Jimmy Fallon sums up the current writing staff well: “[Fey]’s Chicago. Dennis is Harvard. She’d do more jokes about having sex with a hobo, and he’d do more jokes about robots and sharks."

Gothamist on Tina Fey. And we like the book, Live from New York: An Uncensored History of Saturday Night Live, as Told By Its Stars, Writers and Guests.