The extension intercepts any request to your xml feed, be it a feed from tt_news or any other extension, and redirects it to Feedburner so that you can track statistics, enhance your feed republish it in other formats, add Ads or whatever else services Feedburner will add in the future.

The extension checks whether the requesting client's user agent is Feedburner or a feed validator, in these cases the original feed is delivered. In all other cases like browsers or feed readers the requesting client is redirected to the Feedburner URL.