The Universal Edit Button is an icon
which shows up at the right end of the address bar of your web browser whenever you're on a page with editable content. It works on any website which supports the Universal Edit Button. Currently, it requires that you use Firefox and install the UEB Firefox plug-in.
For more about the UEB, see http://universaleditbutton.org/
Just click on the icon and you'll be in edit mode for the main card of the page you were on.