It's a cool looking site for sure! Well done!
@Forogramero I think your question and @Silvestrus question can both be answered by the Ad Units Extension. I believe both are custom HTMLs and I am pretty sure you can set ads to be displayed by user levels, and in this case, it's just custom HTML Scripting. Clever use of it if it is that, otherwise, I would be REALLY interested to know what the underlying script itself is, if it's pulling directly from Flarum.
Well done @neon_eddie