So, are you going to provide built-in things like: IPython viewer (like http://nbviewer.ipython.org/), LaTeX viewer for notes (like http://mathb.in/), support for slides (this thing would be awesome - to have possibility to view them and view/fork their source; a bit related to http://slidewiki.org/) or something in that line?
We have similar ideas for integrations with those tools, with the exception of latex. With latex, we have our own online editor with some neat git integration.
