I wish I had an answer for it. I tend to look at the music scene, specifically electronic, for a relatively successful model: the DJ as filter (curator). I'm not sure that such an equivalent can be achieved with movies let alone books.
I do think a lot of it will have to come from self promotion and word of mouth (whether by actual mouth or electronic) will become more and more important. It's already almost impossible to navigate the Kindle store if you don't know what you're looking for and that goes for other similar services (Amazon Prime Streaming, Netflix, Hulu, etc.). For example, Netflix ratings in my experience are pretty decent indicators of the quality of most movies, so for some crowdsourcing the value of media may work. (You need a good algorithm and a large enough data set of rated movies.) Others may choose to go more with suggestions from readers whose taste they trust.
What I'd like to see is literary reviews that are accessible to the common reader and that do not assume that you've read the book. This is similar to a lot of the book/movie criticism out there, except for the last clause which is imperative for finding a good book rather than analyzing an already read one.