I built https://taaalk.co which looks a bit like Sonar but for text based long-form conversations - so skimming is possible.
The current site is content-less as I had to change servers.
Previous content can be seen on archive.org (https://web.archive.org/web/20210316214650/https://taaalk.co...)
I'm going to be reuploading the content and getting the community started again, so if you want to sign up to it please do and I will email you when it gets going. (A good place to sign up is on the Start a Conversation page, where you can leave your details for other Taaalkers to start talking with you).
It really makes a lot of difference especially with podcasts since people tend to enunciate a bit more than usual and end up adding micro-silences that can easily add up into minutes.