question about subscribers vs. downloaders

[addictedtorace]

Hey everyone,

I have a question about podcast statistics.

If someone is subscribed through my RSS feed, and their aggregator downloads a particular episode, will that action show up in my Web logs as a hit to that MP3 file?

In other words, when I look at the number of times the MP3 of a certain episode has been downloaded, does that only indicate that people who go to my Web site and manually download the show? Or does that also people subscribed to the show?

FYI - I have read previous discussions about figuring out the number of listeners by dividing total bytes by the size of your files, etc. But I was still unclear on this one point...

Thanks for your help!

Carmen

[jeffoest]

Hi Carmen,

When I first read the questin I thought, hey that's pretty simple, I think I can answer that - then I thought about and realized that I also wonder about the answer.

I THINK the answer is that you see hits on your mp3 files from your subscribers. Now, saying that, I can't help but think - why would feedreading software ping an mp3 file and not just ping and compare the XML file. If the XML file has a different date-stamp, THEN go ping the mp3 files...

So, long answer for I dunno.... People who know: bring it.....

[Steev]

No matter how people are getting your MP3 files, whether by direct download or subscription, they should all show up in your web server logs. Unless listeners are sending the files to each other, you'll see all of your hits.

The "dividing by total number of bytes" argument was one that I made previously because if I just put the URL to your MP3 into winamp, it'll stream the mp3, requesting it chunks at a time. You'll see requests for the mp3 file but the file size won't be the total size...It's like "half" a request. Same will happen if somebody cancels the download of the MP3 midway through. By dividing by the requests by the total bytes from those requests, you can get a reasonable average.

[addictedtorace]

Ah, thanks so much Steev! :)

[docsnavely]

if you are looking for any easy way to know exactly how many subscribers you have, just run your feed through feedburner, and advertise your feed as the feedburner feed......

that way it will tell you how many subs you have.....

i.e., i have say, 550 subscribers per feedburner, and after a day or 2 of having episode #8 posted, I have a total of 620 complete exits or complete downloads of episode #8. i know then that 70 people downloaded the episode but aren't necessarliy a subscriber.....

i hope that made sense.....

[Steev]

How does Feedburner count "subscribers"? Is it unique IPs that request the RSS feed? That could include some guy with a web browser who clicks a link just once; not necessarily a subscriber. It's probably a reasonable approximation though. It's quite difficult to get accurate 'absolute' numbers from your web logs...the best you can usually do is recognize trends.

[jeffbearer]

The trick I'm using to find out how many people are downloading the episode from a link on the website as opposed to people using feed catchers is that I have the episode link go to an intermediate page that forwards to the mp3. then I look for that intermediate page in my logs for direct downloads. and to find the people who get it from the feed is the difference between the total mp3 downloads and the hits of the intermediate file.

You also need to pay attention to the http status code. Only status codes 200 or 206 in most cases are downloads. Others are just pings, etc.

[Patrick]

if you are looking for any easy way to know exactly how many subscribers you have, just run your feed through feedburner

This is not true at all. They use a formula just like everyone else.

A) No one can tell you EXACTLY how many subscribers you have.

B) Any subscriber count is going to be way short of the number of total listeners you have.

[overclocked]

1) *Unless* some intervening service (such as iTunes) is actually cacheing your file, which has occasionally been rumored, every file delivered whether by direct download or subscription will be in the web logs.

2) As pointed out, only count log entries with status codes 200 and (unlikely) 206.

3) Note that some web servers do not accurately report bytes sent -- some will report the number of bytes in the file, regardless of how many were sent, so an aborted or broken download may appear to be a full one.

4) I don't know about feedburner, but some stats engines primarily look at the "user-agent" (a tag identifying what software is doing the download) to determine whether it is someone downloading by a web-browser or someone using something like iTunes or iPodder. This latter will be regarded as a "subscription" even if it is only used for one file. While someone who religiously downloads every episode from the website will not be considered a subscriber.

5) As Patrick pointed out, there's no *exact* way to determine how many subscribers you have, but outfits like feedburner and libsyn have invested a lot of time and energy into refining their mechanism for identifying these numbers. The main thing, anyway, is to identify trends, so as long as you use the same algorithm over time, you should get an accurate view of trends.