I feel like setting up the social media is a solved problem. And while getting users is hard, if you hook up to the fediverse, you can piggy back off other Platforms. I think the harder problem is making it profitable

> if you hook up to the fediverse

No this is the hard problem. HN people live in a bubble. Anything else than signup with oauth and then having access to everyone and its too hard and 99% of people will click away.