Comment by bunderbunder

Actually effective, human-powered recommendation systems already exist, and they’re great.

My favorite implementation of this is talking to the clerks at my neighborhood bookstore. But the New York Review of Books is an alternative that’s easier to enjoy from home. For romance novels I like the blog Smart Bitches Trashy Books. Also this is kind of cheating but I have a family member who reviews books for a library journal so a lot of the time I just let her tell me what to read.