So I remember 2 different periods of the web where it seemed like they were dominated by one particular advertiser

One was 2000-01, with the X10 wireless camera that was pitched as like a “nannycam” to watch your servants as a disclaimable front for clearly being intended for intrusive sexual voyeurism. Also they kind of made the “pop-under” ad where a new browser window opens but is not brought to front

The other was 2005ish SnorgTees, which were nerd-reference or double-nerd-reference t-shirts worn in vertical ads featuring these 23ish models with geek-girl hair acting bouncy and ignorant that they had E-cup tits