Having "back" as part of its name is little justification, in my opinion, for having the backspace key bound to the Back action in Firefox. I cannot count how many thousands of words I have lost from blog entries and forum posts because I pressed backspace when I mistakenly thought that the edit form was in focus. Perhaps the only remarkable thing about DisableBackspaceNavigation, a Firefox extension which does exactly what its name suggests, is that it took this long for someone to think of it. Of course, this could be done with extensions like Keyconfig for some time now, but if the backspace snafu is your only complaint as far as keyboard shortcuts go, DisableBackspaceNavigation is the extension for you.