Bespin proposes an open extensible web-based framework for code editing that aims to increase developer productivity, enable compelling user experiences, and promote the use of open standards. One can read this here.
Bespin’s initial prototype includes support for very basic features, but one can easily notice its power. Its all drawn in the canvas, every character, cursor blinks, scroll bars, text selection, etc. As a Vim user, I immediatly thought of Vim commands/keybindings in Bespin.