What do fluctuating subscriber numbers mean?

I recently helped David, who runs a nice recipe site at ChefPla.com, setting up his blog feeds with FeedBurner. The problem with his rss feed was the lack of reporting available in standard website statistics software. When using something like AwStats, which is what most hosting companies provide, you can only see the number of hits on your rss feed. FeedBurner provides a little more insight in how your rss feed is being used.

David noticed some issues with his rss feeds. I thought I’d share my response here with you. Here’s part of the e-mail I received from David:

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There are a couple of issues I have noticed with the rss feed.

• The number of subscribers is below 10 still, but it fluctuates from day to day so I do wonder how accurate the information is.

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The fluctuating subscriber numbers in FeedBurner are easy to explain: the provided subscriber count is simply the number of people who have accessed your rss feed on any given day. This might come as a shock to some of you, but not everyone is on the internet every day. So, a rss feed subscriber count of ten, two days in a row, could mean you have 10 subscribers. But it is also quite possible that the ten people who accessed your rss feed on day one are not online the second day. Ten other people might have accessed your feed on the second day, bringing your total subscribers count to 20 people.

The problem with accurately tracking the subscriber count is the limited information available to the feed provider. The only things we can track are the software used to read the feed (although, as pretty much any information send over the internet, this can be faked) and the ip address of the computer accessing the feed. I don’t think there is something similar to the cookies used in browsers in use in feed reader software, and even if there is: this would still not guarantee a 100% reliable way of tracking subscribers. I think the service provided by FeedBurner is as close to reliable subscriber tracking as you can get.

But even if we know that the reported subscriber numbers aren’t very accurate, we can use the reporting available to look at the bigger picture. Over time, if you are doing it right, you should see a general upward trend in the reported subscriber numbers.