alt Hacker NewsImagine a website not being a trojan horse, but directly serving non-targeted advertising to users at the same level as their content.
They could target it by tailoring it to content they're serving, just like I'd be ok with seeing an ad for a new car when I'm on a page reading about the properties of a given combustion engine.
Advertising itself is a trojan horse. The entire purpose of advertising is to influence you into doing things that are in the advertisers interest instead of your own.