title: Standard and reliable way to track RSS subscribers?
body: <p>What's the best way to track RSS subscribers reliably <em>without</em> using Feedburner? Some of the obvious approaches like tracking by IP or by the number of hits have some fata flaws. IP addresses can change with each request or multiple users can use the same IP. Also, feed readers can request a feed multiple times per day or even hour. Both problems make it really hard to get reliable stats on unique subscribers. </p>
  
  <p>I've read articles by both <a href="http://ask-leo.com/is_there_a_way_to_track_unique_subscribers_to_my_rss_feed.html" rel="noreferrer">Leo Notenboom</a>  and <a href="http://www.tbray.org/ongoing/When/200x/2003/05/25/Subscribers" rel="noreferrer">Tim Bray</a> on the topic, but none of their suggestions seems to really solve how to track subscribers in an accurate and reliable way. Leo suggests having a unique ID generated programatically to be appended to the RSS feed URL for each time the referring page is loaded. Tim advocates having RSS readers generate a unique hashtag and also has suggestions ranging from tracking the referrers to using cookies. A unique URL would be reliable, but it has two flaws: It's not a user-friendly URL and it creates duplicate content for SEO. Are there any other reliable methods of tracking RSS subscribers? How does Feedburner estimate subscribers?</p>