Dave Winer points out that Radio Userland tracks RSS subscribers today. And as I work with Radio, I constantly discover fascinating new features tucked inside. But while a Swiss Army Knife is a handy tool to have in your pocket, you shouldn’t try to use it for every task.
So at the risk of being presumptuous, I have to ask whether the Userland solution is the right way to count RSS subscribers. Business wants control over critical infrastructure, and referrer logs provide that control without introducing any new dependencies. At the very least, the RSS producer should be allowed to specify a host for the Web Bug simulator for XML. Plus, I don’t see how the simulator allows counting of anonymous users.
On the other hand, I suspect that conventional web server referrer logs are a problem for hosted weblogs. Hosted weblogs are the entry point for new voices on the web. And too many will succumb to weblog infant mortality without the positive feedback provided by referrer logs.