Eu encontrei um rápido "tuto" sobre isso, aqui está o link:
link
Method 1: Shorten URLs via the Opera address bar using custom search It’s easy to create a custom search in Opera. But here I prove you can use it for more than searching! Create a custom search that posts to http://is.gd/create.php using URL=%s as your query string.
Click OK, and you can now create a shortened URL directly from the Opera address bar by typing u and hitting Enter, assuming you used “u” as the shortcut key. Here is my original blog post with more detailed instructions: http://my.opera.com/BAMAToNE/blog/2009/10/04/how-to-shorten-urls-from-the-opera-address-bar Method 2: Shorten URLs via custom Opera button
After my blog post became famous (thanks, Espen!), Opera Community member mistressEVIL furthered my idea and showed us a way to shorten URLs using a custom button. I think it’s a great idea because not everyone is comfortable customizing Opera the way I have shown. But using a custom button is easy because it just takes a click.
Here is mistressEVIL’s blog post with more detailed instructions on how to create custom buttons: http://my.opera.com/missevilat/blog/2010/01/15/shorten-url-with-a-button