I love the idea of a literature SE site. As an English teacher and a novice literary critic, I think it would make for a wonderful place to discuss ideas related to literature. Philosophy has one, math has one, but what about a forum for serious literature students? (Or even avid readers?)
Anyway, why not take it one step further and allow for comments based on particular passages of a text? Annotations for lines or words, even. Those annotations could then be voted up or down, and spark a healthy exchange.
I'm working on an open-source project that tries to do this sort of thing, called HyperLit. I would love if there were a way to incorporate some of this project's plans for annotation with the wonders of SE.