Why Podcasting Metrics Matter: The RSS Enclosure Tag
The entire podcast industry runs on one tiny XML tag that nobody owns. The enclosure tag is why podcasting stayed open when everything else got platformed, and it's also why measuring an audience is so much messier than anyone admits.
I cover where RSS and the enclosure tag came from, how Spotify spent big trying to control the medium anyway, why a download is not a listen, and what Podcasting 2.0 is doing to extend the open standard without breaking it.
I run a podcast. I mean, you're listening to it right now. And I genuinely don't know how many people heard that last episode. Not approximately, not within some margins. I really don't know. I get a download count and that's about it. And the wild thing is that's not a bug in how I set things up. That's just how podcasting works and it's... It's been that way since the beginning And it traces back to a single XML tag that somebody added to a spec on Christmas Day back in the year 2000 This is the Tyler Woodward project. I'm Tyler all opinions are my own and today I
want to talk about the RSS enclosure tag What it is why it matters and why Spotify spent a billion dollars trying to build something that would replace it and basically gave up. Okay, so RSS, real simple syndication. If you've been on the internet since the early 2000s, you might remember it. A little orange icon, feed readers, Google reader before Google up and killed it off. The idea was that instead of going to every website manually, to check if there was something new you subscribed to a feed your reader checked
the feed new stuff showed up it was good and then it mostly died for regular people once social media took over and platforms decided they'd rather curate your content for you but RSS didn't die in podcasting It became the foundation of the whole thing The reason is one little tag the enclosure tag Dave winner added it to the RSS spec on December 25th 2000 which you know is Christmas make of that what you will What the tag does is attach a file to a feed item,
you know, it's normally Normally, an RSS item is just text. Title, description, a link. The enclosure tag says there's also a file here. Here's where it lives. Here's how big it is. Here's what kind of file it is. And that's the whole invention. Attach a file to a feed item. Adam Curry, who was an MTV VJ in the 80s and 90s, is also a genuine tech nerd. He built the script. In 2003, that would look for audio enclosures in RSS feeds and automatically pull them into iTunes. Somebody coined the word podcasting. Apple shipped native support for this in iTunes
4 .9 back in June of 2005. Get this, a million subscriptions in 48 hours. The entire medium took off on infrastructure that nobody owns. Nobody owns RSS. The specs copyright was assigned to Harvard's Berkman Klein Center back in 2003 under a Creative Commons license. No company holds it. You can read the spec right now. Implement it yourself. Ship an app tomorrow. No permission, no license fees, no no proprietary garbage. That's genuinely unusual. The foundational infrastructure
for an entire industry worth billions of dollars in ad revenue and there's no entity that owns it or can take it away from you. What that means practically is that when you subscribe to a podcast, you're just giving an app a URL. The app checks that URL for new episodes. When it finds one, it downloads the file. Your server delivers it. And that's sort of the whole transaction. Apple doesn't have to be involved. Spotify doesn't have to be involved. Unless you're hosted on one of those platforms, the file goes directly from your server to the listener's device. So,
Apple can pull your show from their directory. I mean, that happens and it matters because that's where a lot of people find the stuff. But they can't take your feed down. They can't stop your existing subscribers from getting new episodes. Compare that to YouTube where your channel gets terminated and it's just gone. Or Spotify exclusives where the show only exists if Spotify decides it exists. The broadcast parallel is actually pretty clean here. I mean, think about it, nobody owns the FN band. It's public airwaves. The FCC regulates it, sure, and can yank your license, but the underlying infrastructure is shared.
Podcasting RSS is sort of similar. The rails are shared. You just have to host the files somewhere. Okay, but Here's the thing. I can't get over I Said I don't know how many people actually listen to my last episode that's because in podcasting a Download is an uh, you know an HTTP request your server sees an IP address a user agent a timestamp and how many bytes get served from the server It doesn't see whether anyone hit
play. It doesn't know if the file set on a phone for three weeks and then get deleted because it was never played. There's no session. There's no callback when someone finishes. In radio, and I've worked in radio for a little while now, we have Nielsen, PPM meters, diary surveys, panels. It's imperfect, but... PPM has well -documented sample size problems in small markets, and if you've ever looked at the margins of error in a Nielsen book, you've had a small existential crisis, but you know at least something. You have a number you can defend to an advertiser.
Podcasting has the IAB TechLab podcast measurement guidelines. Try saying that five times fast. Four versions now. The latest is from early 2024. What they define is a process for cleaning your server logs to get a more defensible download count. De -duplicate by IP and user agent within 24 hours and force a minimum byte threshold filter out known bots. What you get at the end of that process is a number that more accurately represents deliveries not listens deliveries again downloads
Spotify knows your age bracket. They know exactly where you dropped off on an episode They know if you skip the ad that's because they own the client in the server They see everything If a platform owns the whole stack, you get real analytics. If you want independence from the platform, you're working from server logs. Spotify understood this, which is why they started back in 2019. They went on a massive spending spree. Gimlet for around $230 million. Anchor for around $154 million. Parcast, The Ringer, Megaphone, Podsights, Chartable. Joe Rogan went exclusive in December
of 2020 for a reported $200 million plus. Total spent on the entire beta test cleared billions of dollars. The bet was that if they could pull enough listeners into Spotify with exclusive content, they could migrate the medium off of open RSS standards and onto something they controlled. It didn't work. The Obama production deal ended and went to Audible for wide open distribution. Brene Brown's show left exclusivity and moved over to Vox Media. Rogan's renewal in early 2024
was explicitly not exclusive. He went back to Apple, YouTube, Amazon Music all on the same day. Spotify said it was the last exclusive podcast deal they'd ever do. One thing worth knowing, when Spotify bought Podsites and Charitable in 2022, those were the only two third -party measurement platforms that worked across publishers and advertisers. Charitable got folded into megaphone and shut down. So Spotify The dominant non -apple listening platform now also owns a big piece of the neutral
measurement infrastructure everyone else was using. RSS didn't fix that. That's a platform layer problem. The protocol has no mechanism to address. The other thing I find interesting is podcasting 2 .0. Adam Curry and a developer named Dave Jones started it in 2020. It's an open extension to the RSS namespace, so it layers on top of the existing protocol and doesn't replace it. It adds transcripts, JSON chapters, direct micro payments via the Lightning Network, live streaming support, globally unique episode IDs. Apple shipped support for it. and iOS 17 .4,
at least for the transcript part. The first time they adopted an open namespace tag rather than inventing their own proprietary version. Spotify drugged their feet for a little while, but added it later that year. The mainstream apps are moving slowly. Nobody's done the micropayment stuff at scale. but the direction is keep the open protocol, add structured features on top of it, and don't try to instrument the listener. That's a choice. A download is not a listen. It's never been a listen. The entire podcast medium has been running on that vagueness since 2005, and
20 years in, It's still not resolved. I've been thinking about this because I'm literally on both sides of it. I work in broadcast where the measurement is imperfect, but at least something exists. And I run a podcast where I get a download count and I'm supposed to generalize from there. The same design choice that makes this show impossible to the platform is the one that makes it impossible to fully measure either. Not really separate problems, same decision and I'm not sure I'd trade it because I've watched what happens when
a platform owns the whole stack and decides the economics don't work anymore. The billion -dollar siege failed. The 24 -year -old XML tag is still running, still doing its thing. Thanks for listening to the Tyler Woodward Project. This is an independently produced and written podcast by myself, and if you'd like to support the show and project, head over to tylerwoodward .me forward slash subscribe and become a member today. It goes a long way. Makes me feel all loved and stuff a little warm and fuzzy inside. You can also follow me on Instagram threads and blue sky at Tyler Woodward dot me
I'll catch you guys next week
