The thing about Feedburner subscriber numbers is that Feedburner has to rely on the feed readers to report accurate numbers. If a reader doesn’t report or reports incorrectly, then the whole Feedburner stat is thrown off. In reality, subscriber numbers are even less useful to track than page views (my in-depth review of how Feedburner reports numbers on Search Engine Land explains why reach (the number of people reading your feed each day) is a better indicator of audience engagement than subscribers (for instance, since the total subscriber number includes those who subscribed but never read and those who subscribed on one service, then switched services and subscribed again).

Feedburner could make it easier. They could have handy historical charts for reach like they do for total subscriber numbers. Not that it would do that much good. We would continue to measure subscriptions like we do page views — more is better! Even if it’s not.

That the total Feedburner number is made up of lots of individual services with their own quirks makes measurement difficult as well. I would love to be able to see historical charts by service, to make it easy to pinpoint anomalies within trends. For instance, when Google Reader doesn’t report numbers one day, that’s not obvious from the overall count, but is when you compare subscriber numbers by service by day. But the only way to do that is to click through to each day and look at the pie charts. Or if you’re super geeky, you might manually put all the numbers into a spreadsheet.

Take this week. My total number went from 1279 on Monday to 1450 on Thursday. Just looking at the overall numbers, it looks like my subscriber base was steadily growing:

But then, Friday’s numbers dropped down to 1321.

What happened?

The only way to tell is to dive into each day’s numbers. Compare Monday:

to Tuesday:

Everything looks about the same except that my Netvibes subscribers went from 181 to 305. (This was around the same time they released their newest version in private beta.) This new Netvibes number stayed pretty constant on Wednesday and Thursday, but on Friday, dropped back down to 182.

Who knows what happened. Maybe Netvibes was double counting those users who moved to the new private beta (counting both their old accounts and new accounts)? Maybe upgrading their database just caused a glitch. In any case, it appears that the anomaly has been corrected.

Of course, this same type thing will happen (without correction) anytime a new service opens. People who previously had subscriptions on other services will try the new one, causing double counts. Which is part of why Rick Klau is right about reach being a better indicator of reader engagement. Although my total subscriber count went down yesterday, my reach number was way up (likely thanks to the fact that I actually wrote something for people to read).

Did anyone else notice a bump in subscribers then a subsequent dip this week? Or am I the only obsessed one?

As I mentioned last week, I recently talked with Rick Klau of Feedburner and dug into where all the subscriber numbers come from. From that came my write-up at Search Engine Land about the details of Feedburner subscriber counts. As I said in the article, fluctuations tend to be due to client-based readers (if people don’t turn on their computers one day, they don’t get counted) and occasional non-reporting from a feed reader (I may not notice when My Yahoo doesn’t report my 15 readers but I’ll definitely notice when Google Reader doesn’t report my 513).

Does posting more often help?
This means that new posts shouldn’t impact numbers because the feed readers count subscribers based on actual number subscribed (web-based) and number of requests to see if new posts exist (client-based). Whether or not a new post is there to pull in doesn’t make a difference. (Of course, if you have a new post that people like and link to, that may cause others to find it who then subscribe to your blog, so posts can definitely increase numbers. It’s just that the feed readers themselves don’t count based on whether they actually pull a new post or not.)

Rick said not to fixate on day to day numbers, but instead look at overall trends, so I thought it would be fun to take the opposite of his advice and fixate on the details. Last week, my numbers looked like this:

(Thursday is so low because Google Reader didn’t report numbers that day.)

And for the entire month, pulling out a select group of feed readers, my numbers looked like this:

(Google Desktop and Outlook are client-based, so fluctuate based on whether or not the person turned on the computer and opened the application.)

For the month, my overall subscriber numbers stayed pretty constant, with a slight upward trend. (One interesting thing I noticed that there are two days that Google Reader didn’t report numbers that impacted overall Feedburner numbers (Nov. 3rd and Nov. 8th); but two other days when Google Reader non-reporting didn’t impact overall numbers (Oct 15th and Oct. 29th). Maybe Rick will come by and let us know what was up with that.)

But how many are reading?
Looking at subscriber numbers over time isn’t the same as looking at site visits over time. Subscriber numbers tend to add up. You stop reading my blog, you may not unsubscribe. You might just stop clicking on the site in your RSS reader. You start using Google Reader instead of Bloglines, that old Bloglines subscription continues to be counted. Which means that it’s not all that likely that your subscriber numbers will go down over time. If they stay relatively flat and just creep up a little like mine are doing, you may not be getting new subscribers, so big upward spikes are obviously good.

Reach, however, does tell you how many people are reading your feed on a given day via a feed reader, so that may be a better number to use when measuring adoption over time. Unlike total subscriber numbers, reach numbers do seem to be impacted by whether or not a new post is available. And that makes sense, if you don’t have anything new to read, you won’t have many people reading it. Not everyone reads their subscriptions every day, of course, so you’ll get some people catching up on old posts on days you haven’t published anything new.

Here’s how much reach numbers look and it’s clear that they’re all over the place, probably based on when I have new content.

When you post can make a difference here. For instance, on several days, I posted at night, so most people seemed to have read those posts the next day (such as October 27th and October 30th).

It also appears that days that a particular feed reader doesn’t report numbers impacts the subscriber counts but not the reach counts. This makes sense also since Feedburner aggregates subscriber numbers reported to it, but gathers reach numbers itself.

Looking at per-feed reader numbers
My numbers seem to tell me that while my subscriber counts have gone slightly up over the last month, the actual number of readers I have via subscription have remained basically constant. The last two days look a little depressing, but I’m betting the low numbers are due to a combination of no posts and weekend reporting.

Another thing these numbers show is that web-based feed readers are fairly constant, so if one of them doesn’t report numbers for a given day, you can pretty confidently add the previous day’s number to the total Feedburner count to get accurate stats. With this method, I can infer that I actually had 1049 subscribers on November 9th. Of course, you could just wait until the next day. (Ack! I mean, yes, of course — wait. Perfectly reasonable.)

One thing that’s interesting is that while most of the feed readers trended slightly up (Google Reader went from 468 to 513 and Netvibes went from 133 to 145), Google Desktop was sharply down over the period (67 to 17 — see the purple line in the graph below). Is this because Google Desktop users in particular aren’t fans of the blog or because overall Google Desktop usage is down?

And that’s the other tricky thing with these types of numbers. You are at the mercy of the feed reading services, and changes in usage or reporting may impact the numbers in ways you can’t control.

Overall though, up and to the right is probably a good sign and Rick clearly is right when he says not to obsess about the minutia. Fortunately, I’ve done that for you.

I admit it. I have a problem. It’s possible that sometimes when I wake up in the morning, I reach over to my smartphone and skim the internet a bit while I try to convince myself that I should actually get out of bed and be a productive person. And maybe, every so often, I check my blog subscriber numbers. I blame Feedburner for the obsession. There’s nothing to be done about it now. It’s morning, coffee, Feedburner. It’s just all part of waking up.

I had talked with Rick Klau from Feedburner a couple of weeks ago to see just where the numbers come from. When I woke up this morning and saw that my stats had once again run off to parts unknown (possibly St. Lucia), I figured this morning might be a good time to post that article and let everyone else in on the details.

So, if you’re interested in just how Feedburner comes up with its subscriber numbers, and why some days we wake up to morning, coffee, and a sad, sad stats state, head on over to Search Engine Land and check out How Feedburner Adds Up Subscriber Numbers.

My feedburner numbers went down by more than half overnight. I considered spending the day crying in a corner, feeling abandoned and alone, wondering where it all went wrong, but first I thought I’d check a few other sites. Their numbers went down by around half as well.

Did half the population unsubscribe from the internet all of once? Nah, Google Reader just didn’t report numbers for yesterday. Compare my Friday subscription numbers:

to Saturday’s:

Everything looks about the same, except that those 511 subscribers from “Feedfetcher” are conspicuously absent. Reader reports numbers by including them in the request when it grabs a feed. Likely it didn’t include those numbers with requests yesterday due to some kind of a glitch. I’m sure it’ll be fixed soon. Occasional non-reporting of numbers by feed readers is one of the reasons Feedburner numbers tend to fluctuate.

(Note My Yahoo didn’t report numbers for Friday, but since I apparently don’t have many readers on My Yahoo, I didn’t notice.)

Or maybe there’s a “Google Reader subscribers unite in unsubscribing from the internet!” movement, but I’ll give it a few days before heading to that corner with my ocean of lonely tears.

Update: Feedburner has confirmed this as well.