Apologies for the silence. I've been working on the layout for the last few days. Something that's always gone wrong is the design of the site itself, so my hope is that by creating a complete static layout first before I start programming the backend, I won't be worrying about making a frontend the entire time. Time will tell if this strategy works.

Part of the activity problem is definitely just how difficult it is to actually keep yourself in hte habit of checking multiple sites, especially when sites these days are specifically designed to be addicting and draw away as much attention as humanly possible. That's why I wanted to create an aggregate site that let you link multiple accounts together and freely browse several sites simultaneously, at your leisure. Do you think that would help, or do you think that's not going to help much?

>I wanted to find a way to let people enjoy it enough to make them want to create a paid account
I've considered a few options.
The easiest is just... "Don't bother?" People can still enjoy most of the features without paying money, it's just that you are a passive observer without a paid account.
Another option is restricted free accounts. These accounts can't upload anything(but a PFP,) but CAN interact. They'll probably be forced on a trust system where their initial couple hundred interactions need to be approved first before they become public. This still could be abused though.
A different vein in the restricted free accounts is free accounts that allow you to create playlists and subscribe, but nothing else. This is the hardest one to abuse, but I'm not sure that this would be enough.

I'll be honest, launching it as free and making it paid wasn't exactly a hard option for me to pick. An earlier incarnation of the idea was exactly like this. I also planned to just give everyone of world2ch and a couple of other places free accounts anyways.

>The state of the web
I wonder why image boards are the only ones that survived outside of Japan.
My planned site doesn't really fit into any of these. It's closest to a revival site, but it's a revival in concept only. I'm just trying to take a bunch of discarded features from classic YouTube, and use that as my starting point, while mixing in new features(the aforementioned audio. I'll also consider image posts but I think that I might make an art site instead for that.) I wonder how that will affect my site. Maybe I'll end up with something that is just unique enough to draw new people, just like the two sites you had mentioned.

>Share
You could do it. I'd be interested in checking it out, though unfortunately most social media doesn't appeal to me so I can't say I'd stick around.

>Followers should stay private, because that’s important to avoid becoming like modern social media.
Now, I'm curious. Why do you think visible follower counts have caused such a degradation of modern social media? Every site I can think of had public followers, but the degradation only started happening around the time of Facebook(at least, from what I've seen.)