I'm pretty sure it has been mentioned before that yes, you'll be able to use emacs keybindings. The editing surface is based on CodeMirror http://codemirror.net/, which is very customizable.

The problem right now is that the editor runs in a browser and so the shortcuts for emacs conflict.

Why the fuck should a text editor be running in a browser?

It's using webkit as a rendering engine - while it's in beta, that means a browser (although on mac it runs standalone). I'm pretty sure they've mentioned that Windows & Linux will be a standalone app before the final release.