The problem at that point becomes you start to implement a service, rather than a protocol. I'm not sure there is necessarily a solution for identity with the way email is currently implemented.

Is there any encryption for notebooks/notes?

Quiver 2 saves all data in plain JSON files. So if you have turned on FileVault on Mac, the data files will be encrypted. Otherwise no.

In using the beta, I haven't noticed any actual performance/battery difference between the two. Honestly, when I first installed it the first thing I noticed was the lack of sound when changing the volume.

It's still there, but now you hold shift+vol up/down to hear the feedback. This is in contrast to earlier OS X versions, where holding down shift will mute the audio feedback.

Heh, me too - you can turn it back on in System Preferences though. It's a new sound effect.

Do you know exactly where? I couldn't find it.

I don’t have Yosemite, but in Mavericks, you can change it in System Preferences > Sound > Sound Effects, by checking the checkbox “Play feedback when volume is changed”.