Almost perfect Rated 4 out of 5 stars
I agree with the remarks of Walid Damouny. I would add that the extension needs an easier way to specify the fallback URL shortener instead of modifying the correspondent key in the about:config page, for the sake of less experienced users. I could not find a Preferences button in the Addons page in Firefox. Other than that, this is almost perfect.This review is for a previous version of the add-on (188.8.131.52-signed.1-signed).
Thank you for your review! I agree that setting the fallback should be easier. Sadly, the Add-ons SDK framework (https://addons.mozilla.org/en-US/developers/docs/sdk/1.1/) does not yet support a "preferences" button and form, so it is sufficiently complicated to add a settings panel at the moment. There is an open enhancement bug (https://bugzilla.mozilla.org/show_bug.cgi?id=645207) on the matter, but it does not seem to be currently active.
I'll keep investigating how I can make the settings available more easily within the restrictions that the Addons SDK makes! Suggestions greatly appreciated!