The dictum says, "You can't tell a book by it's cover." CoverSpy, a blog on Tumblr, says that's a lie. The team is comprised of "publishing nerds" who swarm the streets of New York City to see exactly what people are reading. They check the subways, the streets, The Grey Dog’s Coffee on Carmine, some podiatrist’s waiting room, newsstands, parks, bars. If you're on the F Train and happen to be reading, you can't hide from these spectators. They'll call your book out, and your outfit.
While the posts border on a sort of distant stalker-type mentality (Did that sound nice enough? I'm not trying to make them sound creepy), it's a good source if you're in need of a new, popular read. If you're one of those people who browse aimlessly in Barnes & Noble, just looking for decent covers to pull you in to a new novel, this might save you some time. Or, if you frequent NYC and want to make an appearance on the blog, make sure to dress nice and smile while you're paging through chapters. Here's a recent observation: The Fortress of Solitude, Jonathan Lethem (F, 20s, blue boots & dove-gray jeans, looking v. serious, F train).
So start representing your books well, everyone. You never know who's on the lookout.
(Not creepy. Right?)