Matter past the event horizon falls into the singularity pretty quickly, and that's a mere dimensionless point in space. But the singularity's spin does have an

Matter past the event horizon falls into the singularity pretty quickly, and that's a mere dimensionless point in space. But the singularity's spin does have an effect on spacetime around the black hole, in effect creating a second (much stranger) type of event horizon called an ergosphere. In a way one could say that rotation changes the shape of the black hole and that property can be observed from the outside to determine the spin. This is cool because, while pretty much everybody was certain that black holes do spin, this hypothesis was not yet backed up by data. The phenomenon doesn't have anything to do with quantum information leaking out, however. I didn't get to see the actual announcement but my guess is that effect of the spin on spacetime has now been actually observed in the wild.