Personally I find this user experience annoying and counter-intuitive. It makes the links, and the scroll bar indicator, inconsistent, by destroying any notion

Personally I find this user experience annoying and counter-intuitive. It makes the links, and the scroll bar indicator, inconsistent, by destroying any notion of "how far down the page" you are. Furthermore, returning to a page after visiting a hyperlink usually induces a bunch of jumping around as the page rebuilds (and often the browser ends up showing some other view anyhow). Finally, it comes across to me as though some programmer decided to get fancy, rather than as a considered solution to some actual problem with the page's load performance. In short, to date I have always found it a flashy hack, not an enhancement of my web experience.