Last month, StumbleUpon unveiled Su.pr, a tool that shortens URLs but also enables the submission of links to StumbleUpon while also offering the option to simultaneous update Twitter and Facebook.
Now, Su.pr has been made available to anyone. To access it, you must become a registered user of StumbleUpon. You'll also need to authorize Twitter and Facebook to use the tool, if you plan to use the simultaneous updating. (And seriously, why wouldn't you?)
Like other URL shortening services, you can see how many times the link has been clicked on, which is highly valuable.
Especially useful is the bookmarklet that you can use to make the process of submitting to three different social networks at the same time even easier.
Now, all I need is for someone to make a Su.pr Greasemonkey script for Google Reader so I can reduce the step of clicking the links I want to share to open in a Firefox tab. Who's game?