Description of problem:
There is no option currently in gnome to tile windows horizontally and vertically so comparing several documents at once is slower.
Probably include a menu that shows up to allow a user to tile their windows when they right-click on the gnome window list?
if you hold down shift while you move and resize windows, they snap to tile positions.
This isn't really within the scope of the sort of work we do on Metacity at Red Hat. There's at least one upstream Metacity bug about tiling, see External Bugs field.
For GNOME 3, the GNOME Shell design document available from:
has a section "Window Control Gestures" where it describes a gesture for side-by-side tiling. It also has placeholders for keybindings to tile all the currently active windows. (If you search for 'tile' in the document.)