I got the idea for The Final Key one day punching in a password and thinking about how neat it'd be if my keyboard was able to store the username/password credentials, since it'd work with all existing applications. So I made The Final Key on this premise, it acts as a USB keyboard, and can be controlled through a serial terminal or a dedicated GUI application, it works on Linux, OSX and Windows. I finished building the prototype a day or two after the mooltipass project was announced, so The Final Key could be considered irrelevant, however, it's a slightly different approach to the same niche problem, and the workflow is different enough that I believe there's a place for both in the world.
Logging in is easy:
"Trigger" an action on an account (for example: type all for Facebook)
The device blinks (that' not actually a step)
Focus the username textfield and press the button.