Finding a podcast is easy; finding relevant episodes is harder. If you want to find, say, all of Paul F. Tompkins's guest appearances, or podcast episodes about the Russian Revolution, try the podcast search engine Listen Notes.
Photo via Gratisography
Listen Notes is a no-nonsense search engine with a database of over 18 million episodes from over 300 thousand podcasts. Search for any topic that might be discussed among multiple podcasts.
Say you want to find a few episodes about the Erie Canal. The results page includes a rich card for each episode, including a stream, download link and subscription links. You can sort by relevance or date. (The latter choice is useful to check in on the same search now and then.) You can also choose single-episode results, or podcast title results.
Click on a result for a more thorough episode description and the podcast's general description. Each podcast is also tagged with its iTunes categories.
Listen Notes works great on mobile too, making the transition from result to podcast app much less painful: Just copy and paste the RSS link, or tap the iTunes link to open in Apple's Podcasts app. Unfortunately, this only gets you to the podcast, not the specific episode, but that's still better than any other search engine we used.
Developer Wenbin Fang built the app and runs it on his own. He plans to polish the UI and add community features and possibly in-episode audio search, he told me over email. He's deleted his early mobile app versions, but hopes to eventually relaunch them.
Fang compares his current database to Google's, which in 1998 indexed 25 million pages -- not much more than Listen Notes's 18 million episodes. "I don't know, maybe someday Listen Notes will become as big as Google. Haha," he writes on the Listen Notes about page, and it honestly seems like it has a chance. There are a couple of other decent podcast search engines with shinier interfaces, run by bigger teams, but they share a fatal omission -- one they could easily fix, but which reveals that they're not trying to be the Google of podcasting.
Audiosear.ch lets you filter by date, duration, category and network, and includes in-episode audio search (based on automated transcription) for some shows, which is impressive when it works. Stitcher search is better for certain searches, such as finding podcasts about the podcast "Welcome to Night Vale".
But neither of these sites link to a podcast's iTunes page or RSS feed. (Stitcher lets you add it to the Stitcher app.) To add the podcast to your favourite app, you have to search for it all over again.
That's one pain point too many, and it shows that these sites have a different business plan; Audiosear.ch wants to be the engine behind other apps, while Stitcher wants to build its own exclusive ecosystem. For the rest of us, the best option is Listen Notes.