[bbx]

Other examples include http://www.apple.com/iphone-5c/ and http://www.milwaukeepolicenews.com .

Trent Walton actually wrote an article about it: http://trentwalton.com/2013/10/23/scroll-hijacking/

I myself sometimes trigger animations depending on the scrolling position. But I don't depend upon the exact scrolling position to show or hide elements. I, like you, don't like this trend. It's like a vertical slider, where you can only stop at pre-defined positions.

It reminds me of custom scrollbars implemented in Flash or JavaScript that act completely differently, especially slowing down the scrolling movement (you need to turn your mouse wheel 10 times as much to scroll one single page).