FeedBurner is a free service for those with RSS/Atom feeds that allows publishers to enhance their feeds in a variety of interesting ways. I have signed on. By republishing their feeds through FeedBurner, publishers gain detailed feed statistics, maximum feed format compatibility, and"shockproofing" to absorb bandwidth spikes. A number of other features are available such as their Amazon Burner that inserts your Amazon Associates affiliate ID into any links to Amazon.com product listings automatically. FeedBurner also automates the handling of subscriptions from any format, greatly simplifying a complex process.
I talked with their CEO, Dick Costolo, who said they are building a platform to set the stage for variety of future services as the RSS movement is just beginning. He added that one increasing trend is the increasing integration of tools and services as developers and vendors establish connections, greatly simplifying the landscape and start-up requirements for the user.
One thing I liked about their statistics was the detailed explanations of each term. This makes them very accessible. This type of attention to user needs is sometimes lacking in blog related tools in this initial stage of tool development. Feedburner provides statistics on several things. The click-through stats are provided on an item basis so you see which posts are driving the most traffic through them. I would imagine this would be especially interesting if you were looking for revenue associated with click-throughs but it is still interesting for anyone. They also show the various feed services (e.g. Bloglines, NetNewsWire) used by your subscribers with an explanation of each provider.