Pack before the web most places doing ads had them al, in house, salesmen (mostly male) design and so on., large byers (mcdonalds) might hire an agency to talk to all the little newspapers, but even the little ones did this in house.

> most people publishing a website either cannot or do not care to host the ad server on the same domain, they just want to monetize the site.

That's sort of beside the point, though. The site owner's commitment to running ads is useless unless there are people to view them, and, as long as unsafe ads are ubiquitous, the only safe advice to give to people is that they should run ad blockers everywhere. It doesn't matter that that isn't what the site owner wants to happen.

Who said anything about an ad server ?

An ad is a particularly sized JPEG that you place in your images directories… and then point to with an HTML tag.

Everything we tried to build for you was lost once you deviated from that level of complexity.