I planned to write about this early this week, but I honestly forgot about it. It's related to a post I've read on one of Martin's blogs just last week I think. The post in question gives a link to a list of feed directories that you can use to submit your RSS feed to.
So I've done that and the very next day I watched the stats on FeedBurner. I noticed right away that an increase in subscribers took place the day before, but when you look at the agents that grabbed the feed, thing tend to fall into place. You probably already now that if you click the link right under your subscribers count, the one that says, "See more about your subscribers", you get more information about what agents have accessed your feed. For example, in my case, the subscribers count was 21. What can I say, I'm not a very popular guy. If you add up numbers in the "Feed Readers and Aggregators" table you get that total. But that is not the number of real persons that have grabbed your feed, because if you look lower, there is another table that shows the "Web Browsers". In my case the total of the browsers was 8: 7 with Internet Explorer and only one Firefox. In my opinion, even that number is wrong, As certain bots might disguise themselves as browsers. But I could be wrong. And speaking of bots, the last table on the page shows the bots that have accessed your feed. So if you add these with the number of browsers that have been registered, you get the exact number of subscribers that FeedBurner states you have. Witch is wrong from my point of view. It's like saying that Google Bot is my number one reader.
I was at the peek of exaltation thinking that I've found a huge gap in the way FeedBurner shows stats. But before shouting my knowledge to the world, I decided to do another comparison, using another day as example. I numbered the total of web browsers and the number of bots and then added them together and then ... my whole theory collapsed. I got a number larger that the one that FeedBurner showed to me. So what's up with that? Seeing as I can get no real facts out of this I decided to read the official help pages. Maybe I should have done that earlier.
Here's what I got from the first shot: "Subscribers is an approximate measure of the number of individuals currently subscribed to your feed." Ohhh, why didn't you say that it's approximate. That makes a lot more sense. Reading on: "Subscribers is not computed for browsers and bots that access your feed." There goes all my mathematical operations. And the last but not least: "Subscribers counts are calculated by matching IP address and feed reader combinations."
So that's how I managed to waste a whole hour of my day. The lesson to be learned here? There's a reason for those question mark icons: if you don't know something, all you have to do is click them.