UPDATE: Fixed in OS X 10.8.
The "Swipe between pages" gesture for a mouse and trackpad (as configured through System Preferences) do not navigate forward and backward through your history in the Mac App Store (as they do for Safari). I can't tell you how many times I've tried using these gestures there to no avail.
Will it be fixed before OS X Mountain Lion is released? It's looking pretty unlikely.
Apple, please fix that.
Observed up through an including Mac OS X Lion 10.7.4.