Yeah I went a little too fast myself and so, started reading the comments because I was confused. I thought the loading progress bar was actually a good thing and a UX improvement when waiting for heavy pages to load.
Regarding using such a bar as an indicator of page-scroll progress, I'm indifferent. It's not intrusive, so if I don't care for it, it doesn't bother me. For those who do care for it, I think the horizontal positioning is easier to gauge page-scroll progress because looking up is easier than looking all the way over to the right of my viewport (I never look over there because I use a scroll-wheel or touchpad to do the scrolling ;)
Regarding using such a bar as an indicator of page-scroll progress, I'm indifferent. It's not intrusive, so if I don't care for it, it doesn't bother me. For those who do care for it, I think the horizontal positioning is easier to gauge page-scroll progress because looking up is easier than looking all the way over to the right of my viewport (I never look over there because I use a scroll-wheel or touchpad to do the scrolling ;)