Auralphonic Episode 28: How Platforms Affect Podfic. Dated: April 2017.
I ignored the LiveJournal stuff at the beginning, tbh, but there’s a tie-in with the one host’s vidding experience and YouTube. My Little Pony podficcers are on YT, but more communities that the hosts can think of don’t tend to use YT (including copyright issues, especially for those who include music).
Through trial and error, Tumblr has an upload limit around 10 - 15 MB, which probably can’t handle more than a 10 - 15 minute podfic. Most people don’t host solely on tumblr because it seems more based around songs than podfic itself.
The bit about Flash isn’t true for AO3 anymore (episode is from 2017, and the phasing out of Flash happened in 2020). This platform has affected where some people choose to host (so they can easily post to AO3), coming up with podfic posting stuff ([Podfic] Title), and what they include (some read the content warnings).