Firefox about:config

I just found the about:config feature in Firefox. While searching google for a way to disable the backspace key in Firefox. (see about:config for details) I came across the Mozilla Support Forum

You don't know how many times I was in the middle of a post and pressed the backspace key and lost everything.

To disable the backspace key:
1. type about:config into your url bar.
2. find and double click browser.backspace_action
3. replace the "0" (zero) with a "1" (one)

That's it.