Yes, Listen Notes is making some money - not a lot, but enough to cover all the cost and bring in a bit profit as of today.
The basic idea is that Listen Notes should be free to 99% of users, while making some money from 1% of super users.
We run ads (obviously) on the website and we provide API: https://www.listennotes.com/api/pricing/ And I've been experimenting some paid features that are needed for PR/marketing/journalists to do their job, e.g., https://www.listennotes.com/datasets/
And today is special, because on Sep 16, 2017 (Exactly 2 years ago today), I started to work on Listen Notes full-time!
Just curious, is your company still one-person?
Here is the pricing page: https://www.listennotes.com/api/pricing/
Granted those assumptions, you've got to get pretty far up Maslow's Hierarchy of Needs to hit "rent a WeWork"
Looks like it's an ad-driven revenue model, and it looks like it gets ~ 1m views/month: https://www.similarweb.com/website/listennotes.com
Assuming $1 per 1,000 impressions, we get $1,000 / month.
That's purely the website. I can't speculate on the API side of his business though.