May I add that I tried auto-scrolling on Palm's Ereader (back in the days when I was still a sucker for DRM-ed books that you were only allowed to read on the platform they chose to port their reader to) and didn't like it very much.

I found it impossible to get the scrolling speed right, but that's probably due to the fact that I have a weird reading style, alternating between speed-reading and sucking in the atmosphere really slowly. I also tend to jump back and forth a lot which, astonishingly, hasn't been translated into an auto-scroll pattern yet.