(UPDATE) Triton Digital analyzes the effect of “podcast caching”

The original version of this article, and Triton Digital’s whitepaper, included iHeartRadio as a platform which caches podcasts. The whitepaper has been corrected with the note below, and this article has been amended also.


In the whitepaper “Podcasting: Content Caching & Transparency” issued via this blog on 12/5/17, we inaccurately referred to specific distributors including iHeartRadio, Spotify, Google Play and Stitcher as caching podcasts.


We have since been advised by iHeartRadio that caching is only employed at the specific request and agreement of the publisher:


“iHeartRadio pulls podcast content from the hosts RSS/XML feed and does not re-host or cache any podcast content, unless requested or agreed to by the publisher. Each time a user plays a piece of content, iHeartRadio makes a call to the hosts feed, which will allow any podcaster to dynamically insert ads on iHeartRadio. Further, iHeartRadio has been committed to leading the industry in a push for better data & technology, which will increase a podcasters ability to target ads (and content) based on geographic location and demographic.”   – Chris Petersen, Senior Vice President, Podcasting – ‎iHeartRadio

In a whitepaper released yesterday on its blog, Triton Digital explains how podcast caching challenges the growth of podcasting, identifies the most influential platforms which do cache podcasts, and pledges its full support of platforms which move away from the practice.

To understand the import of Triton’s whitepaper statement, one must understanding caching — it is the copying of a podcast file onto another server, from which listeners download or stream the show. Doing that pulls the podcast out of its traditional distribution anatomy, which is usually governed by RSS. RSS (Real Simple Syndication) is the main circulatory system of podcasting, distributing episode links to apps from which people download or stream shows. Those links lead to the podcast’s hosting platform.

Some important distribution points bypass that traditional system, instead placing copies of the podcast files on their own servers. Triton calls out companies which prefer hosting the files within their distribution systems to control the technical reliability of delivering to their users, and also to apply their own analytics to measure listening.

Triton Digital, which provides advertising technology to the podcast industry — notably ad injection of new commercials into entire libraries of podcasts — is hampered when podcast producers (Triton’s customers) partially lose control of the files that some platforms cache.

SOURCE: IAB 2017 Podcast Ad Revenue Study

While Triton has a horse in this race, the whitepaper has a larger focus: the health and growth of podcasting generally. The paper observes that in 2016, ad injection represented 56% of podcast commercials. (That’s number of ads, not revenue.) Cached files cannot participate in this trend; their ads are “baked in” because the injection technology cannot reach the cached files which have been copied from the show’s main host. Revenue is lost, and listeners do not benefit from current promotions (or new edits of the episodes, which Triton also points out).

“The ability to dynamically insert highly-targeted, relevant ads into podcast content has opened up an entirely new revenue stream for publishers, enabling them to dynamically stitch highly targeted pre-roll, mid-roll, and post-roll audio ads directly into podcasts.” the whitepaper asserts. “Publishers can also programmatically back-fill their podcast episodes with dynamic insertion, increasing the content creator’s revenue.”

Triton also identifies an analytics problem, in an audio category already somewhat hobbled by lack of authoritative third-party measurement. Podcast owners and prospective advertisers, whether the advertisers choose ad injection or not, need singular information about number of plays and other, more granular listener behavior like percentage of listeners who hear a midroll ad. When a distribution platform maintains its own cache of a podcast’s episodes it also maintains a proprietary cache of listener data.

“The caching of podcast content by third-party distribution services bypasses the publisher’s ability to monetize their content. In addition to not being able to target ads on the listener level, publishers also lack the ability to provide advertisers with transparent and centralized analytics. ”

Triton acknowledges a “very important role” for the platforms it calls out, but concluded with this: “However, due to the downsides of caching podcast content outlined in this whitepaper, we fully support third-party directories and aggregators moving away from it.”


Brad Hill


  1. It is my understanding that both Stitcher and iHeartRadio are moving away from caching podcast episodes already. The holdouts are Google Play Podcasts and Spotify mainly today. Yes, agreed it breaks the growing dynamic ad insertion developments in the podcasting industry. I agree that all caching should cease and primary hosting be dominant in the medium for all listening unless this caching offers so economic advantage to the content creator.
    Rob Greenlee
    Head of Partnerships at Spreaker.com and BlogTalkRadio.com

  2. It’s true that Caching is a bad thing, advertising-wise, but I think tracking reach and downloads is the bigger problem. Especially for smaller, independent podcasters like myself. It’s hard to get a read on how large your audience is when sites like Stitcher pull the file and create a whole different set of analytics that have to be checked. These third party podcast aggregators are becoming more and more important and iTunes continues to lose it’s status as ‘the place’ to get podcasts. Most of my listeners don’t even get the show from iTunes anymore… which used to be the one place everyone wanted to be. It’s changed a ton in the 10 years that I’ve been doing my show… and I’m glad to see that, especially when it makes the shows for accessible for listeners and introduce new tools for podcasters.

    Matt “WhiskeyBoy” Blake
    Host – WhiskeyBoy Radio

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