I built MyTube.FM with very simple CodeIgniter MVP + MySQL, as a fun after-hours project.
The biggest challenge was getting audio recording to work on as many devices as possible, but I am sure not all have been worked out :|
The main idea is that I would like to have some sort of Twitter that would be more genuine than what Twitter is right now. I also think that making people force to use their voice not only brings more emotions into discussion but also helps combat trolls as it takes much more time and energy to record your voice, rather than type a message.
This is very new project and I currently only cultivate handful of profiles myself in hopes of bringing traffic; for example POTUS profile: https://potus.mytube.fm/
I did the project myself and would welcome all ideas how to take it off the ground (I am programmer not a marketing whiz unfortunately), so please feel free to reach out! Perhaps thanks to HN, I could find a founding partner?