This is a cool idea. There is a feature I've been looking for in a url shortening service. Vapurl is half way there with the expiration after a certain amount

This is a cool idea. There is a feature I've been looking for in a url shortening service. Vapurl is half way there with the expiration after a certain amount of time or number of visits, but what I'm looking for is to change the url after those conditions are met. Say, for a user-contributed coupon/deal site, I want to give users an incentive to post, so I'll let them put in a shortened url redirect to their affiliate links in the post, but after x numbers of clicks or a set amount of time, I want to switch the redirect to my own affiliate link.