  The outcome of a weak quantum measurement conditioned to a subsequent
postselection (a weak value protocol) can assume peculiar values. These results
cannot be explained in terms of conditional probabilistic outcomes of
projective measurements. However, a classical model has been recently put
forward that can reproduce peculiar expectation values, reminiscent of weak
values. This led the authors of that work to claim that weak values have an
entirely classical explanation. Here we discuss what is quantum about weak
values with the help of a simple model based on basic quantum mechanics. We
first demonstrate how a classical theory can indeed give rise to non-trivial
conditional values, and explain what features of weak values are genuinely
quantum. We finally use our model to outline some main issues under current
research.
