You could open a competing forum, but users of the previous forum would not automatically have access to it, which was my point. You'd have to somehow reach out

You could open a competing forum, but users of the previous forum would not automatically have access to it, which was my point. You'd have to somehow reach out to them to let them know it existed and they'd have to create new accounts and all that. That would be hard to do if you no longer had access to the old forum. With reddit you can simply open a new sub and everyone would already have access with their existing accounts.