If you have a blog, you may already know about FeedBurner, a “feed enhancement service.” I don’t serve my feeds from FeedBurner, but lots of people do.

They’ve always provided some free statistics, and recently enhanced the free stats with ad summary performance and circulation trend charting. But they now have a premium service called Total Stats Pro that adds referrer reporting, detailed item and ad stats, including who’s syndicating your feed. Pricing is pretty cheap.