I actually did a whole report for one of my business classes (It was actually supposed to be a controversial topic) and I did it on the Ratings System.
I am familiar with what Jack Valenti did with the ratings system, what movies became what, and how the ratings became what they are now (I.E. - Spielberg helped create the PG-13 rating, Gremlins would have been rated "R" without Spielberg as a producer, Fritz The Cat was the first X rated motion picture, Andy Warhol's Frankenstein was the first 3-D pornographic film, ETC, ETC) and I was surprised about what I learned.
Film History is a wonderful subject, especially when you consider what kind of hell the people went through (Poor Fatty Arbuckle, and any celebrity today thinks they have it bad if they get kicked out of a new movie project).
It's all fascinating, and ff you were to go into the next topic on the MPAA ratings system (It's eventual, I assume) I'd be just as intrigued as go into it as I did this series.
Great chronicling, Moviebob.