Theme or plugin that resembles this site

I’m putting a great site together but the one thing I’m struggling with is a way to have the public post the main topics, instead of having to start each post on my own and wait for others to reply. I’m looking to do something like this… LetsRant.com …Site is all public comments and would have my moderation. Any theme or plugin for something like this would be appreciated. I’ve been on multiple theme websites and youtube and not having any luck. Forgive me if I didn’t explain it well, just getting back into web design after 10 years. Thanks