The keyboard shortcut to log in/log out: command-shift-L
If you accidentally hit the shift when you mean to bring up the post-link dialog, you're stuck, with no way to save the entry you've been working on. Many entries have been lost thanks to this unfortunate similarity in the shortcuts.
So, please please please, in a future version: consider either changing the shortcuts around to where they are not so similar, or adding an escape from the log in/log out popup.
Please and thank you.