I was a consultant at the time, and wanted to point out how crappy my client's webhosting was (really I just wanted to convince them they were going offline long enough that spending an extra $50 per month on a proper wordpress host would actually make them money)
I kept a twitter thread of all the features I was adding (https://twitter.com/RozenMD/status/1364881512500404224), and eventually it spread via word of mouth. It doesn't make life-changing money, but I could see myself running the service full time eventually.
I ended up moving off of 100% serverless compute, since enough people were using it constantly that it was 80% cheaper to run several servers 24/7.
Took a few hundred hours to implement, we got pretty lucky to find an audience, and it’s too a year or two after making it free to actually start getting recommended by the App Store - I think we must’ve crossed some threshold for getting enough positive reviews, or something. Anyways, I can’t say it’s a reliable way to make money, but I had fun doing it, and it does bring in some money.
Brings in about $100 MRR split between 2 people.
It's been surprisingly successful with other B2B startups.
Not enough revenue to be my main source of income, but it's a nice monthly bonus.