I’m sure there are many who would love something like this and be willing to pay enough to cover costs and maybe generate a full time income for you. Good luck!!
I don’t like the idea that people can’t see my earlier writings. That’s important to me, especially if I don’t share stuff often and I put effort into it. I don’t see the benefit in hiding that from my friends.
What I’m looking for these days is actual community, conversation, and connection. I think the effortless posting on Facebook/Twitter encourages kneejerk garbage (and blogs, sadly, have fallen into decline) so I really like the more “slow down and make something meaningful” philosophy here. If you can turn that into an actual community—one that offers something Reddit doesn’t—I’d pay for that.
We tried something similar [1] a few years ago. The limit is 5 posts per day. Our approach was minimalistic in a sense as you could post links only and no text, pictures, or videos.
We named it Turtle, symbolizing the opposite of the chatty twitter bird. It wasn't so clever from an SEO point of view though.
This is a great way to ensure that the website fails by never hitting critical mass.