This paragraph really nailed it for me:<p><i>"We show that when a charged particle goes in, it adds a soft photon to the black hole. So it adds hair to the black hole. And more generally if any particle goes in—because all particles carry mass and are coupled to gravity—they always add a soft graviton. So there’s a kind of recording device. These soft photons and gravitons record information about what went into the black hole—infinitely more information than we previously believed is recorded by this mechanism. Now whether all information is recorded by this mechanism… I'm pretty sure the answer to that is no, but there are generalizations of this mechanism and then it’s a lot more confusing."</i><p>They're showing in this model that perhaps, the event horizon of a black hold acts like this kind of abacus, pushing the photons suspended at the edge of the horizon a little bit in, a little bit out, recording what has fallen over that horizon during the life of the black hole.<p>That's really, really cool.