The authentication functionality demoed in the screen cast is cool - but looking at the notebook app it seems that it is a Akshell branded system. Are you going to offer customisation of that?
Except how many developers want a random (to the user) shared login? I'm doubtful that logging into a non-Google site with a Google account or using Facebook Connect is yet a standard user experience. The way I see it, this could just confuse users.
Why not provide a login system specific to each app?
I actually think a common login across all Akshell apps is what will make this superior to AppEngine, AppJet etc. Also, it would be good if there was a per user data store in addition to a per application one.
A specific for application login system can be implemented as a library in a few lines of code. But using it will prevent an application from benefiting from the Akshell environment.