@Cat, IIRC, rough sex had nothing to do with it either. The whole thing, supposedly, was an incompetent investigation and a frame by a prosecutor anxious to score a win.
I think it was probably a world rights deal -- for that kind of money, I doubt very much she held onto her foreign rights, and I wouldn't be surprised if film rights were included too. I mean, what do I know, but even with all that, a 4 million dollar advance seems...a tad optimistic.
And absurd. It's not totally a zero-sum game, I know there's some truth to big sellers bringing money into the house for other authors, but when it's this big an advance, you know this is going to suck promotional and marketing $ away from nearly everyone else.