I remember reading somewhere that a blogger should value each RSS subscriber at a certain amount per month. I think it was a dollar. That means that if you have 1000 RSS subscribers, your blog should be bringing in around $1000 from those subscribers.
I imagine that figure depends on the niche of the blog.
I was wondering what is the value of a subscriber on an email list?
Again, I guess it would depend on the niche that you are in. A IM list might be worth more than a Cookery list.