I prefer that over the alternative, which is to start reading some post and having the rest of the loading content push what I'm reading below the fold.
What about if instead of pushing the content down, you get pushed down with the content? If I'm remembering right, Twitter does something akin to that (at least on mobile)
I'm beginning to think that this effect is deployed purposefully - witness the ad banner that doesn't display until the split millisecond before you click on the link that it pushes out of the way. Then again [1].