The feed is meant to keep you looking at Facebook for longer, of course. However, this could also go some way toward popping social bubbles. Much of what you'll see in Explore isn't that different than what you're used to, but it could get you out of a rut where you're seeing the same sources (and thus same ideas) over and over again. With that said, it's not clear how many people will use it when it's buried -- ideally, it'd have a prominent position.