Why does my Feedburner Subscriber Count Fluctuate?

From 1000 subscriber to 400 and so on? How does that happen, and why?

• Why does my Feedburner subscriber count fluctuate so much?
• Are people unsubscribing and subscribing as much as my Feedburner counter says?
• I notice your Feedburner counter goes up and down each day – why?
• My RSS Subscriber Counter Goes Down Every Weekend – Why?

This week, Hendrik from California Blog and DonkeyBlogger (now part of duoblogger) asked me how, and why his feedburner count goes up and down. Since I didn’t knew the exact answer to this question, I went and did some research on this matter.

Here’s how I found the answer to this question:

I found the answer quite simple via google: (check the link in the last paragraph)

“When we report a subscriber number, that represents the total number of individuals who had the feed requested on their behalf on that day.”

Most of these subscribers fall into one of two groups:

1. those using a stand-alone feed reader
2. those using a web-based feed reader

In the case of stand-alone feed readers, that user has an application running on their computer which activates the feed repeatedly throughout the day. We look at characteristics of those requests, and differentiate between repeated requests from the same person (as indicated by regular polling intervals, consistent IP addresses, and common user agents) and different requests (where one or more of the previous data points vary).

In the case of web-based feed readers (My Yahoo, Google Reader, Bloglines, Pageflakes, etc.), those services retrieve the feed repeatedly throughout the day, but do so on behalf of multiple people. Almost all of these services report to us how many of their users are subscribed to the feed. At the end of the day, we tally up how many stand-alone feed readers are subscribed, and add them to the web-based users. The end result is the total subscriber number we report. (I’m leaving a few details out; check the link below for a more complete answer.)

The fluctuations are almost always due to people using stand-alone computers who don’t turn their computer on, or don’t load their feed reader on a given day. If their feed reader doesn’t ask for the feed that day, we don’t see them, and consequently don’t include them as a subscriber.

Finally, for a more comprehensive look at the various components of a subscriber report, there is a post on this found on Labnol. I have to say; it’s from 2006 but you can’t say it aint informative. It also makes some important comments on “Reach”.

5 Responses to “Why does my Feedburner Subscriber Count Fluctuate?”

1. Hendrik says:

   November 13, 2008 at 5:06 pm

   Good post Mark. My reader-count sometimes drops from 15 to 0 in one day. They should work on better algorithms to get a better overview of the total readers.

   Reply
2. jim w says:

   July 24, 2009 at 11:11 am

   cheers for this, i’ve been wondering why i can have 70 readers on day, 45 the next, 65 the next day. bloomin’ frustrating!

   Reply
3. Mary H. says:

   October 11, 2009 at 5:17 pm

   Thanks for this article! I had been wondering this for awhile.

   Just so you know, the link to the techcrunch case study doesn’t seem to be working.

   Mary

   Reply
   • Mark says:

     October 12, 2009 at 8:56 am

     Thanks for the call Mary, this post was written while I was doing my own blog and of course the images weren’t copied from the other server while transferring the database :)

     It seems that post no longer exist so the link heads to Labnol for now.

     Greets

     Reply
4. Jack Yan says:

   February 28, 2010 at 1:12 pm

   Thanks, Mark, for writing this. I can understand the count varying by a little with the two groups of subscribers, say, plus or minus 20 per cent. Jim, in his comment, talks about 70 to 45, so it’s around 36 per cent. But in your opening sentence, we are talking 60 per cent—and I tend to see fluctuations of 75 per cent. These occur not on set days—it could be any day of the week when it comes to my personal blog.

   These wild fluctuations began in August 2006 and ran till January 2007. From there, they were reasonably steady (the sort of behaviour your example could account for) till a two-month period from March 2008. I saw a period of calm after that, until December 2009. Since then, it’s just gone nuts—430 one day, 130 the next.

   In your experience, would it really vary that much—and why were there so many periods of calm, where the count only changed by, say, 25 readers?

   Reply