It depends on the medium. On the desktop it's not a huge deal - I just hit the home button and I'm back to the top. If we're talking about mobile, I agree with

It depends on the medium. On the desktop it's not a huge deal - I just hit the home button and I'm back to the top. If we're talking about mobile, I agree with you partially. In fact, there is a whole lot of improvements to be made for mobile devices, not just scrolling. The recent addition of undoing your vote is a direct result of not having a mobile interface at all, since the arrows are too small to finger. So, instead of creating a mobile version of the site, they "patched" the UX problem. And so a sticky header would only patch the UX problem - the problem being a complete lack of mobile design. It baffles me why a site that is the source of bleeding edge technology news for many of us can't design a mobile site.