The best example in the whole WWW is i my opinion an ebay Auction.

For example: You startet an auction on ebay and now you want to share the auction worldwide and you will to make it easy for your Users to find your auction in the ebay jungle. So all in all do it CURT.LI. You decide to create an CURT.LI URL for this auction which will be free for you and easy for your users.

The ebay URL is:
http://cgi.ebay.de/Motorleinwand-HDTV-240-x-240-cm-NEU-vom-LEINW
ANDKING_W0QQitemZ310199895355QQcmdZViewItemQQptZDE_Elektr
onik_Computer_TV_Video_Elektronik_Leinw%C3%A4nde?hash=item4
8395ac53b

Your new CURT.LI URL will be for example:
http://curt.li/my-auction

What do you think which URL can users remember ???