So you have a website that has an RSS feed–which when a user subscribes to it, automatically tells him or her that you added new content. Now you want to know how many people have subscribed. Furthermore, you might want to be able to tell which posts are receiving the most attention. Typically, you cannot tell how many people have subscribed to your RSS feed just by having one. The beauty behind being able to subscribe to an RSS feed is the anonymity one gets from doing so–unlike newsletter subscriptions where the user must supply you his or her email address. So how can you tell…