I read some (apparently unfounded) http://www.micropersuasion.com/2007/11/could-a-billion.html rumour about the death of TinyURL over the weekend, raising the question of how to reduce our dependence on a single source for short URLs (for those keeping score, this is a bit problem for any resource registry). So I think there should be a distributed approach. Basically, what you need to do to make URL's like http://seesmic.com/QZ1Y7R6h9Q/ work is to (a) write a redirect into your httpd.conf file (for Apache; other servers will vary) and then (b) write a small redirect engine to be located wherever your httpd.conf redirect pointed. You would also need (c) a script that allowed you to create redirect instances. This is well worth doing and is now on my list of things to do (or find).