Today, we see online ads being used as a form of "nag", to borrow the term from the shareware days, to encourage computer users to "sign up" for or "subscribe" to something that is free from ads (but still a means of data collection that may support delivery of ads elsewhere). I have read that YouTube is doing this, as many HN commenters like to try to convince readers to pay.
The utility value of ads to the computer is low. But these users are not the ad buyers so that makes little difference.
The tragedy of online ads is that computers when used for search do provide utility to computer users in locating products and services. But middlemen, so-called "tech" companies, seek to intermediate the use of computers for search in order to profit from ad services. This lowers the utility value of search to the computer user.
HN commenters and other commenters across the web complain about this degradation, namely they complain about results delievered by the largest search middleman, Google, almost daily.
Online ads annoy the majority of computer users in order to be "effective", i.e., profitable for the ad buyers, with respect to only a small minority of computer users. The system is profitable for the ad buyers but extremely inefficient. Waste and fraud are common on an unprecedented scale.
Personally I have nothing against advertising. However, having used computer networks that had restrictions on advertising, I question whether computer networks are the appropriate place for advertising.
The decreasing ability of those who produce software to license it for fees, i.e., no viable business plan, has caused them to use surveillance, data collection and advertising services as a substitute means of generating income. Software is given away "for free" and functions as a Trojan Horse for surveillance, data collection and advertising services. The sustainability of such a strategy is questionable.