Discontinued since Outlook Update!
This is a really simple addon to monitor your outlook email adress. It features a button with a badge that contains unread count, desktop notification and a few options available under the addons preferences. It also utilizes the badge feature, one of the newest additions to Firefox since version 36.
This addon was made mostly for learning reasons, but also for me to use as a stripped-down replacement for a more featured addon, that I don't need and therefore can save a bit of work load.
How to use:
Just be sure to be logged in to outlook and you're already good to go.
Interested in the source code? Don't use Outlook and want it for another email service?
The source code is available at GitHub and due to really basic functionality, the code should be easy to alter for other services.