So, a couple weeks ago, my fingers were aching from the awkward stretch to alt-left arrow to go back a web page and I knew that if the more industrious emacs users of the world had been working diligently that there would likely be an extension for Firefox to map keys from the main part of the keyboard to do this and other simple things. A google search for "emacs firefox" led me to the conkeror project. "Conkeror is a mozilla based web browser designed to be completely keyboard driven, no compromises. It also strives to behave as much like Emacs as possible."
There is indeed is a simple keystroke for moving back to the previous page and all links on the page show a number for quick navigation. The trouble with the tool is that more and more sites try to do more for you -- blogger.com's editor steals C-b (control-B) to put text in bold when my fingers want C-b to move back one character. Gmail's standard mode doesn't seem to respond to the numbered link requests. Gmail does have a basic HTML mode which works fine under conkereror.
I may play with it on and off, but I don't think it'll become my standard browser yet and it's definitely not for anybody unfamiliar with emacs. And people more serious about emacs than I am may end up doing their browsing from within emacs using w3