I've used something similar for my blog community, actually. I'm using Wordpress MU where basically people can sign up for their own Wordpress blog. There's more to it than that, really, but that's basically what it is. Anyway, it isn't quite like what you're using, but what I do is I allow users to put their own ads on their blogs, which shows up on their blogs 50% of the time (the other 50% shows my ads). It works for me because my users get hosting and never have to worry about script management, and they also get to make a profit.
