The more I look at this the more it feels like this is some kind of scam. I wouldnt trust my info to the sign up form.
Given it's a content platform, I struggled to capture the essence with one or two screenshots.
May I ask what made you think "this is some kind of scam"? I'm genuinely curious. Would love to fix that impression if possible.
Not sure why it's hard to capture the essence. Show us the backend and frontend. Use lorem ipsum filler
Say I want to use it to post my cat videos, I don’t necessarily need a demo of that to understand that I can do it.
You have reviews and users. Just use a legit user for the demo with permission of course.