Here's a really simple URL-shortener you can run yourself.
It connects up to Radio2. Like the now-defunct Adjix, it can return stats back to Radio2 that tell it how many times a link has been clicked.
It creates shortened URLs that are actually domains. So it's possible that at some point in the future we could implement this using DNS, making a truly distributed system. However DNS would have to get a new name type, one that equivalences a host with a URL.
This may be on a different server from urlShortener.root.
First, be sure your radio2.root is fully updated.
Then choose Preferences from the Misc menu in the OPML Editor and scroll to the Radio2 section, then to the URL shortener panel. Make sure the first checkbox is checked, and enter the domain of the URL shortener, the same one you entered in the previous step, in the Domain section.