If you are a site owner, you probably like knowing how your content is used, even if this is just an incoming link. One of the nice features of urlB.org is that you can easily tell which urls of your site have been "shortened" by it, just by looking at your server logs!
Here are a couple of entries from my logs:
grep "urlBorg/1.0" < access_log | grep -v HEAD
22.214.171.124 - - [14/Feb/2008:16:48:03 +0200] "GET /weblog/ HTTP/1.1" 200 26385 "-" "urlBorg/1.0 (+http://www.urlb.org/) [lgfy]"
126.96.36.199 - - [14/Feb/2008:16:48:20 +0200] "GET /weblog/2007/12/08/3214/ HTTP/1.1" 200 19345 "-" "urlBorg/1.0 (+http://www.urlb.org/) [lggw]"
Not only I am able to see when a shortcut was created to one of my pages, but I can also see the "URL key" (ex. "lgfy") -using the API I could get extra info about the short URL, like stats, etc.