Push, pull, whatever. It's all a matter of semantics. The short version is that all the spokes remain in tension (except under extreme circumstances), but that the tension in the bottom spokes changes more than the upper spokes.

That is, the three or four spokes near the ground contact point lose a lot (but not all) of their tension, while the tension in most of the other spokes increases slightly. Some claim that this means the hub "stands on" the bottom spokes (because they react more); others say that since everything is in tension, the hub must be hanging. I'll let you decide which way you want to present it.