I would prefer that ads NOT be the same as regular posts to prevent people from mistaking promoted ads for actual content. Reddit was really bad about this, you would click a thing thinking it was legitimate only to find out it was an ad after the fact. I want my content and my ads to remain separate. They need to be clearly marked (not stealthily marked like on reddit), the ratio of ads to content should heavily favor content, and they need to be dismissible.

Maybe admins could start with opt-in ads that they ask if you want when you create an account? Very few people would accept them but some would and even tho it wouldn't cover the costs it could help a bit. You definitely shouldn't just enable ads for all tho