I might suggest your "buzzfeed for books" comparison doesn't do it justice. Perhaps "Pinterest for books" or "Reddit for books"?
As feedback, a few thoughts off the cuff: - I'm hesitant to auth Twitter, because you ask for permission to post but don't do the thing where you promise never to post on my behalf without advance warning. - I think the "shelves" model is interesting. I'm definitely interested in what David Bowie found interesting. Maybe not so much Art Garfunkel (though IIRC he is an obsessive reader so who knows) - It would be interesting if there was some cut where, for a given book on a given shelf, you could see other popular/relevant shelves it was on. Sort of the way Twitter surfaces tweets in your timeline that were liked by a friend. - Maybe a view of just books, not shelves. - I want to see what others had to say about these books, not just whose shelves they're on. Maybe that comes later, when you have more activity? - Looks like you can add a book to your reading list, "heart" it, or "heart" a whole shelf. This is a slightly confusing information architecture, vs. something like on Airbnb which has a clear architecture of saving properties you like to a list. Might want to refine that a bit.