Hi, one thing I've noticed (not only on AC but on other sites which use the same theme) is that there is a bug with the responsive design of the site's current theme. On screens deemed too small to accommodate the sidebar (e.g. my iPad in portrait orientation), the site doesn't quite fit the width of the screen. As a result, the page can be dragged diagonally when one attempts to scroll.
On a desktop, resize your window to portrait orientation, and you'll notice that the bottom scrollbar is present until the window is wide enough for the sidebar, showing that the bug is related to the responsive ness of the theme.
I'm sorry if I haven't explained this very well.
Just try the site on an iPad, and you'll see what I mean.
Offering a non-responsive version of the current theme until the bug is fixed would probably alleviate this issue.
On a desktop, resize your window to portrait orientation, and you'll notice that the bottom scrollbar is present until the window is wide enough for the sidebar, showing that the bug is related to the responsive ness of the theme.
I'm sorry if I haven't explained this very well.
Offering a non-responsive version of the current theme until the bug is fixed would probably alleviate this issue.