Vimperator is a Firefox browser extension with strong inspiration from the Vim text editor, with a mind towards faster and more efficient browsing. It has similar key bindings and you could call it a modal web browser, as key bindings differ according to which mode you are in. For example, it has a special Hint mode, where you can follow links easily with the keyboard only. Also most functionality is available as commands, typing :back will go back within the current page history, just like hitting the back button in the toolbar.