[lobocinza]

> It's currently not economically possible to listen to user's conversations, transcribe them to text, and serve ads based on that.

Anedoctally I belive Meta does something like that because I consistently get ads on Instagram about topics I talk with a friend on Whatsapp and sometimes that is done completely via audio messages. Though I might be wrong and leaked the topics in text messages among other possibilities.

I think it can be economically feasible. They can have a model optimized for their topics which can be orders of magnitude faster than general-purpose speech recognition. Low accuracy probably wouldn't be an issue as they are able to fine tune the user topics of interest via its interactions with the ads (e.g. click rate, time spent before scroll).