Here's a great FAQ page from FeedBurner as well as links to other resources explaining RSS on CNN, Wired Magazine and Forbes.

I've been touting the advantages of "subscribing" to blogs via newsreading software. No email is involved so you sidestep the problem of spam filters and undelivered e-newsletters. I use and recommend NewsGator as a newsreader (aka news aggregator) for its simple interface. But the truth is there hasn't been an easy way to figure out how many people are "subscribed" to a blog. Nor exactly who they are. In contrast, you know who signs up for your ezine or e-newsletter because you are collecting email addresses. When you send out an HTML newsletter, most email service vendors offer you detailed reporting on who opened a particular issue, what articles they clicked on, etc. Needless to say, marketers love this.…