Really useful :) Rated 4 out of 5 stars
Really useful but I wish it had 3 more features:
1. Have an optional button that can be placed in a toolbar or selectively in the add-on bar.
2. Have an optional icon that can show up in the address bar.
3. Use the above mentioned buttons to expose the short URL if present without shortening the long one (my most wanted feature).
I'd really like to use this extension for its name's sake. There already are URL shortening extensions from their respective websites and also a tonne of other extensions that do the same thing but this is the only one I found that actually copies a short URL if present.