I'm kind of missing this feature which I use all the time in Visual Studio when browsing through the code, inside my browser (it's Ctrl+-). So how is such feature supposed to work in a browser?
The page is loaded and the top part of it is displayed. You use in-page navigation controls like scroll, page-up/down, home/end etc. The page-up/down have this nice property of reversibility, they are mutually dual, would I say. This "reverse motion" feature is missing for home, end and scroll.
Edit: Example of workflow, where the described feature 'd be needed:
You hit the Home key to look back for information you saw previously (esp. on long pages), or you hit End key to come to end (where next chapter, See Also (on wikipedia) or other information of interest is located, as you expect), then you want to go back where you was reading previously. How? Or you can hit those keys by accident, not sure why, but sometimes I mistake Shift+Ctrl+End for simple Shift+End and there is no way back (other then rolling the page to look for where the selection starts).
Other (painful) case is searching in Firefox. You get focus to the search bar (by Ctrl+F for example) and start writing the word you'd like to find. Firefox immediately reacts by scrolling the main view to the first match to your (partial) input, possibly not finding the whole term, but the scoll position is already screwed on the last match, or match with a torso of your search query. Now how to get back?
Is there a solution? I haven't find any other then implementing it on my own (I'd use Alt+up), for which I don't have time now.