Hmm. The internet created much of it.
Search engines don't like simple straight answers - the page, and site must have "enough" text. Adsense pages have a minimum length, while writers have stretched and stretched to make the weakest pages long enough, with synonyms, ideally with intro, ad, distraction, filler, discussion of last week's recipe, the pan set with affiliate link, and a load or two before you see the key point and leave. If they can squeeze in another 40 words they're allowed another ad block.
Trouble is, there seems little sign that the escalation out of control is peaking... Even though adsense is not quite the blight it once was.