Nice effect, but the fact the page becomes blurry when I have my mouse over the "next page" button is annoying. I have to move the mouse away while reading and back when I want to turn the page. I'd prefer to just not move the mouse and roll a scroll wheel. (Actually, that's a lie - I'd rather not touch the mouse at all and just press j.)
I see that blurring too. I'm using Chromium 14.xx on Linux (yeah, it's old). Makes it impossible to hover the mouse cursor over the "next page" button.
I've seen many other CSS effects suffer from the same issue. This apparently happens when the element is rendered to a texture first and then applied to the screen using a filtered texture sampling (in the GPU).
Doesn't happen here; the page doesn't change when I move the mouse over the "next page" corner, other than the folding up of that corner. Everything remains crisp. What browser did you use?