By Brian Howard Last week, following a soft-launch the week prior, Random House marched out BookScout, a Facebook app designed to link readers with books they'll like but might not have discovered on their own. The recommendation engine draws on a user's "likes"—both on one's Facebook timeline and then directly through the app. Intriguingly, BookScout is not purely a Random House recommendation engine—it'll tip readers to any book in print, regardless of whether it was published by its own imprint Knopf, Big Six rival HarperCollins, indie McSweeney's or even Amazon Publishing. Though the app's early reviews have been mixed (I've found its recommendations to...