Why haven't spammers caught on to i90.org?

When I put up my i90.org project on the web (a site that allows you to make up your own url like white.house.i90.org and redirect it to any other URL like
http://maps.google.com/maps?q=1600+pennsylvania+avenue), I thought that, uh, adult sites would swarm all over it, and that I'd spend a lot of time deleting the worst entries.

Didn't happen. Maybe the web is not as bad as I think.