Re: So, if someone comes along and copies all the Star War Movies
The difference is that places hosting trailers for movies are hosting a short, specially created clip provided by the copyright owner.
Google are hosting the entire work in a searchable format and will create and provide a "trailer" on demand from any part of the entire work without permission. They made a whole copy. I'm not so sure Hollywood or the music industry would be quite so enamoured to have this happen to their products.
I wonder how hard it would be to automate a Google search of a specific book and "find" the whole book by scraping all of Googles "small, fair use, selections"? You certainly could not download all of a movies trailers and re-create the whole movie. (Although in recent years, watching a couple of different trailers for a movie generally does give you the main gist of the story and pretty much all of the best bits anyway.)