Show HN: Seven39, a social media app that is only open for 3 hours every evening

It's an interesting idea, but if it's only open at a convenient time for a particular group, it's going to lack diverse and worldwide perspectives, and those are important for building a welcoming ecosystem. I doubt giving each timezone its own 3 hours would work, but perhaps rotating the 3 hours each day so that it's anchored on a different timezone would encourage that diversity of content and perhaps even encourage creating connections across timezones.

That said, if you've had success with it in a friend group, perhaps that suggests it's a nice mechanism for a group chat app, rather than for a public social media site?

Why should it have “diverse and worldwide perspectives”? Must a Muslim site be open to all Christians? Must a Japanese site admit me even though I don’t know Japanese? Should a site for Ukrainians be forced to allow Russians?

I do think of this as an opportunity for you to create your own site that meets your standards, however.

You've immediately assumed that by "diverse perspectives" I mean controversial perspectives.

Personally, I enjoy reading about world news, hearing about TV shows I might want to watch that aren't in my language. I enjoy reading cross-language puns and seeing photos of food I don't usually eat. I enjoy seeing people who don't worry about the things I worry about.

If you don't want those things, if you don't want to know what's going on outside, then that's up to you, but I think that's a sad way to live life.