The Feedburner team yesterday has released a new feature their users - map overylay. Map overlay gives you an overview on which country you feed suscribers come from.
The map below shows a sample layout for a feed. The darker the greeen, the item reads that country's subscribers has.
Then we have the top countries table. It shows you the top 25 countries by item view.
This new feature might be useful if you are looking to target ads in your feeds for specific countries.