Many times you would be happy with the text scrolling automatically at a convenient speed. This helps in places where the text is for reading only (like an ebook), where our only interaction will be scrolling the text. I believe, this might help in speed-reading habits also.
To enable automatic scrolling:
:map <F8> <C-E>:sleep 3500m<CR>j<F8>
Press <F8> to start auto scrolling. Adjust the speed in the sleep argument. Press Ctrl-C to stop scrolling.
This would be a great feature if added to Vim itself. Imagine a key, such as SHIFT-K, which when pressed starts scrolling the text upwards. Pressing it again, increases the speed. Pressing SPACE stops the scrolling. A SHIFT-J would do the reverse, that is scroll downwards.
I couldn't see any reason for the ^[ so I deleted it. If anyone can think of why the original was
map <F8> <C-E>:sleep 3500m<CR>^[j<F8> please say so (^[ is <Esc>).
Of course Shift-K and Shift-J (K and J) have useful meanings already, so you would probably want to use different keys.