There was some great debate in the comments when I tackled foreign rights, so let's move on to another sub right. It seems like this is the perfect week to talk about film, since Variety just did a piece on the current state of book-to-film, complete with quotes from Jane! (I always enjoy the Variety lingo--only in LA would we be referred to as a "Gotham-based" agency. Clearly Batman was rights director before me. )
So we've already talked about foreign, which takes up the most time and generates the most deals, but film and television is the big one on a per deal basis in terms of money. On the one hand, a big film means big money for the author (though as Jane points out, not as big as it used to be). That said, the percentage of books that ever reach the screen is tiny. Of those that don't, a slightly larger percentage will have the rights bought but will never be made. Another slightly larger bunch will be optioned--meaning a studio or production company has the right to try to get the funding to outright buy the rights to the material. Options, however, usually lapse before any significant progress is made.
I've heard it said that the ideal situation for the author is for the option producer to get enough traction to keep optioning and eventually buy the rights, but never make the movie. Though I don't know how many authors would really want to lose the upside—significantly inflated booksales—to get rid of the downside—a corrupted version of the story they wrote making it into the world.