I had Tiny URL installed on Firefox but for some reason it stopped working. Puny installs easily and works fine. This app is a must if, for example, you want to send a link to a Google map to someone; those URLs can be dozens of characters long! This is an elegant solution.
It doesn't have to pop up anything. All you have to do is one click and you're done! This is the easiest way to shorten the URLs. The link is short and I love the symbol too. My favorite feature is that I can right click on the links on webpages and copy+shorten url at the same time!
Incredibly useful. The best add-on you're gonna get.
This is possibily one of the most useful url shorteners you can get. It's simple to use, gives you options, it doesn't force you to have an intrusive popup window everytime you shorten an url (giving you just an informing window if you prefer), and you have the added value of using even shorter unicode powered urls. Powerful, yet straight to the point.