Sonibyte Podcasting Blog

Describing the Podcast Market: Part 4 = Popularity and Publisher Strategies

We broke down the 40,000 Podcasts we think are currently available into a set of 15 categories. We then stepped out on a limb and estimated the size of the Podcast market last year at 500 million downloads (see our last post). OK, so which categories of Podcast are most popular and get the most downloads, and which lag behind?

Feedburner, iTunes, and Podcast Alley list which of the Podcasts in their directory had the most downloads. We categorized the Podcasts they listed and calculated what percent of them were in each category. If we assume that the popularity of all Podcasts falls in the same general pattern as it does for these top entries, we get an estimate of overall popularity by category.

The table below gives the estimate we get from the above analysis for popularity by category, along with the distribution we gave earlier for the categories in which Podcasts are published. The contrast between popularity by download and popularity by number of Podcasts produced is interesting:

                                                                                                                                       

iTunes   Podcast Subject Categories	Estimated % of   Downloads	Estimated % of   Podcasts Published	Download/Publish   Percentage Ratio
Arts	6.70%	9.90%	0.7
Business	4.10%	6.00%	0.7
Comedy	16.20%	7.40%	2.2
Education	5.50%	4.30%	1.3
Games &   Hobbies	4.50%	4.10%	1.1
Health	4.60%	3.60%	1.3
Kids &   Family	0.80%	2.00%	0.4
Music	6.40%	16.50%	0.4
News &   Politics	9.30%	8.40%	1.1
Religion &   Spirituality	6.80%	7.60%	0.9
Science &   Medicine	3.30%	3.10%	1.1
Society &   Culture	12.10%	11.20%	1.1
Sports &   Recreation	2.90%	6.30%	0.4
Technology	8.10%	6.10%	1.3
TV & Film	8.80%	3.40%	2.6
Total	100%	100%

If you are considering launching a new Podcast, you could focus on an area that has a lot of downloads and relatively fewer competing feeds. With this strategy, our list above suggests the best areas are TV & Film and Comedy. Instead, you could choose to go where the traffic is and to heck with the competition (aren’t you brave!). Then, you’d pick Comedy (again), Society & Culture, or News & Politics. Note that it looks hard to get much traction from launching a new Podcast in Music, Sports & Recreation, or Kids & Family.

These past four posts have presented an overview of the category structure of the Podcast market, its size and growth rate, and the relative popularity of different types of Podcasts. We have tried to be conservative and to share the evidence that supports our estimates. Please argue with and/or discuss these numbers. Our industry needs more information and an open discussion about its size and composition, if we are going to attract the respect and attention these numbers suggest we deserve.

Describing the Podcast Market: Part 3 = Total Downloads and Ad Potential

So far, we’ve provided evidence that there are about 40,000 “stable” English language podcasts (plus some number of “ephemeral” ones) that were downloaded in 2007 by about 20 million American podcast listeners. How many times did this audience download Podcasts each year and which types did they download most often?

Let’s assume the following things are true:

1. The Podcast market is a Long Tail market that follows a power rule distribution.

2. There are about 40,000 total podcasts in the market.

3. Feedburner’s subscriber statistics cover one third of the top one hundred podcasts.

4. For each subscriber to a Podcast, there are another four people who download its episodes. (See previous posts by us, on this issue.)

5. The average Podcast has one episode per month. (This makes monthly subscription info fit well with annual estimates.)

If these things are true, we can use the number of subscribers for top 100 audio podcasts on Feedburner, to calculate the number of downloads made in 2007. We can fit their data to a power law curve, and estimate the coefficients of the curve. We can then integrate across an assumed universe of 40,000 feeds to get the total downloads for all of these feeds. (If you want to see the charts and math behind this, send me an email!)

Our estimate from this process is that there were about 500 million podcast downloads last year. If 20 million people listened to these Podcasts (per the surveys I mentioned in the last post), they would have downloaded an average of about 25 Podcast episodes during the year.

Of course, downloads were probably skewed and concentrated. The Universal McCann survey I mentioned earlier estimated that about 25% of the Podcast audience made a daily download and 35% downloaded at least once per week. If they are correct, the core 60% of our audience (12 million users) consumes about 97% of all Podcast downloads.

Most Podcasts do not currently carry advertising. However, those that do are earning between $5 per thousand downloads and $50 per thousand. (These numbers are based on our own experience with ad placement and on discussions with other companies in the Podcast industry.) If we pick a median value of $20 per thousand downloads, the English language Podcast ad market was worth about $10 million last year.

We have seen a download growth rate over the past two years within our feeds of more than 75% per year.

At that pace, the Podcast advertising market has the potential to reach a value of $17 million in 2008 and $100 million in about four years (by 2011). While that is still a small market, relative to behemoths such as radio advertising or Web advertising, it is big enough to be interesting!

Describing the Podcast Market: Part 2 = Number of Podcasts and Listeners

The last post described a reasonable way to categorize Podcast subject matter, based on fifteen iTunes categories. There are more than 100 active Podcast directories, and it would be impossible to search, inspect, and categories the thousands of Podcasts they list. Instead, we looked at seven directories that had summaries of their listings by category. We then mapped their categories to the iTunes category system, to get eight independent estimates of the distribution of Podcasts by subject. Based on this data, we made an estimate of the distribution of Podcasts by subject.

This was a list only of what feeds have been created—not which subjects are listened to, most often. The categories with the most feeds seemed to be "social" ones—music commentary, news & political commentary, rants about life or love, personal journals, and other soft stuff that comes from the heart.  Second place went to what I would describe as "education."  This included language lessons, help with personal finance, information on games and hobbies, and podcasts about science, medicine or health.  The last group of categories--but not far behind--was entertainment.  TV & film, and comedy are in this group.

As I mentioned earlier, iTunes has about 2,000 entries for each of its categories. If their catalog is comprehensive (i.e., included every published podcast feed), the Podcast market would have about 35,000 feeds. However, when one compares the listings on the different directories, each has some unique items. It is likely that some Podcast publishers don’t get around to listing on iTunes. So, let’s be conservative and add another 5,000 “active” podcasts to those listed already on iTunes, for a total of 40,000 active Podcast feeds. (English language-only!) Of course, there could be 10,000 or more additional Podcasts that have only a single episode, are no longer being produced, etc.  Some of these “ephemeral” entries could develop into stable feeds.  But most are likely to remain undiscovered, unappreciated, and unexploited.

A recent survey by Edison and Arbitron showed that 18% of the households they surveyed had listened to an audio podcast in the past year.  That suggests that at least 20 million US consumers listened to Podcasts last year.  A similar study by eMarketer apparently estimated 18 million Americans listened to Podcasts in 2007. (I say apparently because the details of the study are available only to those who buy their study.) A recent Universal McCann study says about 30 million Americans have downloaded a Podcast. This study lumps audio and video Podcasts together.  Therefore, I think it supports the figures for audio Podcasts only, from the other studies.

Let’s assume we had about 20 million Americans downloading Podcasts in 2007. How often did they download Podcasts? Which categories did they download the most? We’ll put our guess on the answers to these questions in a future post.

Describing the Podcast Market: Part 1 = Categorizing Podcasts

The podcast market suffers from a sorry lack of reliable and objectively-derived statistics.  There are many reasons for this. One is that a podcast can be hosted and served from almost anywhere in the Web--there is no central repository or clearinghouse for them.  A second is that the amount of money spent on podcast ads is still small.  Until it gets bigger, the market will not attract the kind of tracking and validation services that provide audience figures for TV, radio, or large traffic Web sites. Finally, the biggest distributor of podcasts is Apple, via its iTunes store.  And, as most of us know, Apple is pretty secretive about its products and their performance. As far as I know, Apple does not share any download or subscriber statistics on the thousands of Podcasts it lists on iTunes.

The lack of statistics means that we must be creative if we want to answer questions such as “How many podcasts are available?,” “How many podcasts are downloaded each year?,” or "What podcast subjects are popular?"  We can not get any absolute answers to these questions, but we can put together some reasonable estimates by looking at various podcast directories and feed listing services.

Before starting this process, we need a way to categorize the subject matter of podcasts. I decided to use iTunes’ categories for my study, because they seem to represent a sensible and fairly complete schema. Also, most podcasters upload their feeds to iTunes, and therefore have been influenced by the iTunes category structure:

                                                                       

iTunes   Podcast Subject Categories	Number of   Podcasts Listed on iTunes
Arts	2,364
Business	2,277
Comedy	2,115
Education	2,180
Games &   Hobbies	2,161
Government   & Organizations	2,167
Health	2,362
Kids &   Family	2,219
Music	2,172
News &   Politics	2,162
Religion   & Spirituality	2,223
Science &   Medicine	2,338
Society &   Culture	2,175
Sports &   Recreation	2,325
Technology	2,209
TV & Film	2,176
Total	35,625

(BTW, this series of posts is based on data gathered between May and July of 2008. It is of course quite possible, that iTunes will change their category structure without notifying me!)

I've given above the number of podcasts that iTunes carries for each subject.  Do you find it as strange as I do, that each category seems to have almost the same number of entries?  Does this mean that Apple "trims" old podcasts out of its directory after a while, to keep the list for each subject from growing too big?  Or, has Apple constantly juggled and redefined its categories, so that they stay the same size? I'm relatively new to this industry and would love to have help on this question, from someone who has observed iTunes longer than I have.

If you are interested, you can find similar category lists on Podfeed.net, Blast, Odeo, Podcast Pickle, Zune, Podcast Nation, and Digital Podcast. (Note that I am only studying English language Podcasts in these posts. There are many directories in other languages, that I have not addressed.) Each of these directories has its own variations and oddities—partly because each is oriented towards its own sub market within the podcast space.  Still, we can consider each of these lists to be an independent estimate of the distribution of Podcasts by category. By combining category data from these seven directories with the information from iTunes, we were able to build this estimate of the overall distribution of Podcast publishing by category:

 

                                                           

 

 

iTunes   Podcast Subject Categories	Estimated % of   Podcasts Published
Arts	9.9%
Business	6.0%
Comedy	7.4%
Education	4.3%
Games &   Hobbies	4.1%
Health	3.6%
Kids &   Family	2.0%
Music	16.5%
News &   Politics	8.4%
Religion &   Spirituality	7.6%
Science &   Medicine	3.1%
Society &   Culture	11.2%
Sports &   Recreation	6.3%
Technology	6.1%
TV & Film	3.4%
Total	100%

It makes sense to me that the biggest number of published Podcasts is in the Music category. Music is where Podcasting got its start, and many Podcast listeners are well-educated on musical and other audio subjects. (Our company, Sonibyte, was started by musicians!) Society & Culture made sense as number two, since this category contains all types of personal commentaries, rants, and Web-cast radio shows.

As I struggled to map the data from the smaller directories to the iTunes categories, I found three categories that were especially troublesome:

ð Arts: Apple includes literature, performing arts, and visual arts in this category. The latter group overlaps with the TV & Film and Entertainment categories that other directories use. Apple also includes fashion it its Arts category. Other directories put these Podcasts into their Society & Culture types of category. There is a large group of Podcasts that relate to story telling or serial novel creation. These should probably be in the Arts category, but some directories also put these into a Society & Culture category or into a separate literature or storytelling category.

ð Government & Organizations: No one else besides Apple seems to have this category. I didn’t see any entries from this list on Apple’s list of top podcasts. Since I can’t match it up anywhere and the traffic from this area is probably not that high, I dropped this category from our study.

ð Health and Science & Medicine: iTunes splits health-related stuff into self-help, fitness, and sexuality topics (Health) and scientific/factual stuff (Science & Medicine). Spiritual approaches to health go into the Religion & Spirituality category. This is complex enough that I suspect a lot of entries in these groups overlap or are classified differently in each directory.

In our next post, we use this directory-driven data as one source for generating some market size and segmentation numbers.