I was always thinking, best way to motivate users to post is to have some reward for each post.
That can be virtual currency. Like, getting 10 currency per comment, 100 per vote, 100 per debate, and 300 for winning a debate. This is just example. Doesn't have to be these numbers.
However, virtual currency is only as good as virtual stuff it buys. If it buys nothing, then no one will enjoy it much.
So what are best virtual items?
Then it occured to me. A lot of games have virtual pets.
Just imagine it, if you could be active to earn currency, and then being able to buy virtual pet.
Then this site could also be about collecting virtual pets, not exactly like Pokemon or Roblox adopt me, but similar enough.
And it would be exciting if users could attach pets to their profiles, so when you open someone's profile, you see their main pet jumping around profile photo.
It doesn't have to be limited to just virtual pets. It can also be cars, bikes, characters which can be equipped with cool stuff like swords. And also everyone's favorite purchase: catgirls.
We can basically just make this site also be a game with collecting of characters, pets, and items.
For simple enough design, it can be 2D and AI can design it for start. It has to be some animation tho, not just motionless image.