Hacker News Reader

There needs to be a good online editor before there can be a good online editor with vi mode.

right

Codemirror reigns

Both good online editors have it.

(Ace and CodeMirror).

Cloud9 IDE is a whole service. The actual editor behind Cloud9 is Ace (http://ace.c9.io/#nav=about).

You can try out Ace’s Vim keybindings by opening the kitchen sink demo (http://ace.c9.io/build/kitchen-sink.html) and choosing “Vim” as the Key Binding on the left.

http://gpl.internetconnection.net/vi/

And, for completeness, Emacs:

http://www.ymacs.org/demo/