URL shortener

Other than possibly getting a domain with high PR,, and having a few adsense words on the side, how does anyone make money by hosting a URL shortener site? Is there something I am missing about why people launch these services?

these URL shortening sites have an admin backend where the urls can be changed to something else entirely. People shorten their urls and after a while you go back in via the admin login and make some changes, you with me yet?

check out txtexe.com--url shrinker service
they provide a revenue share with you splitting adsense profits...
ads are placed on a "halfway there" page....
for example
hxxp://txtexe.com/d8fdc2

simple

but its not going to make me or you wealthy being a user but if YOU have 100k people using YOUR url shrink service it can add up...

with the popularity of the micro blogging phenomena there is a market...

I see the possibilities on the backend as far as changing the content of the redirect. But it also seems to be kind of a pain in the ass as far as the work involved compared to the payoff. Thanks guys for responding!