I feel like there are other costs beyond attention and privacy, too. Costs of malware and fraud are also common, but for the sake of argument we can just focus on somewhat more "legitimate" / "non-malicious" ads. (Emphasis on the scare quotes.)
There's the aesthetic cost. If I see an ad on or near a nicely designed or produced website or video, it immediately detracts from the visual appeal.
There's the annoyance cost. I'm personally immediately irritated and annoyed when I see or hear an ad. It affects my mood and my impression of whatever I'm trying to look at or listen to. (I despise it when I'm away from my computer and have a podcast on which ends and instantly transitions to some loud peppy ad for a fast food restaurant and I have to interrupt whatever I'm doing to walk over and shut the thing off.)
For some, there's the cost of paying for a product or service that an ad misled them about. They may pay more than they should have or get something which is portrayed a certain way in an ad which doesn't hold up in reality.
There's the psychological and sociological cost. Ads (especially in video or audio form) present a certain clinical and biased world frame. People usually talk and act in unnatural or "perfect" ways. A young person exposed to, say, hundreds of ads per week and thousands of ads per year may eventually start to subconsciously find that frame normal and expected. Even though they know they're ads rather than non-fiction, I think those things can potentially seep in in some cases.
There are the conflicts of interest and the effects caused by suspicion of conflicts of interest. If I see a "sponsored search result" or "sponsored article", I expect that the source will be less likely to show things which might propose a competing narrative or say anything negative about the sponsor. "Okay, I can't trust this source for anything related to [X], now."
As a corollary to the annoyance cost, there's the fakeness/sincerity dissonance cost. If I'm reading an article or listening to a podcast that's presented as, or may very well be, sincere and truthful, it's a little bit jarring for it to be interrupted with some fake, artificial, marketer-crafted bullshit with superlatives about how [X] will change your life and is the best thing ever. A little hard to take the rest seriously at that point.
I feel like I could list at least ten more. From a purely subjective and personal perspective, I don't even mind the egregious privacy implications as much as all these other things. I just fucking hate seeing and hearing ads.
> For some, there's the cost of paying for a product or service that an ad misled them about. They may pay more than they should have or get something which is portrayed a certain way in an ad which doesn't hold up in reality.
This is a big one. Something being free with advertisements doesn't mean that we're not paying for it, just that the way we're paying for it is hidden. Companies don't pay Google money for altruistic reasons, they're paying because they can earn more.
If you think about it, we're actually likely to pay more when we pay through ads. Google wants X dollars. In a subscription model, we pay X. In an ad model, a company gives Google X, because they think they can make X + P (profits). So they get us to buy a product we don't need, and in order to recoup their loss we need to be paying the manufacturing cost M (we'll pretend other costs like transportation and retail markups are included in here as well), plus X, plus P. Otherwise the advertising isn't worth it. Instead of us paying X to Google to us their products, now we're paying X+P+M for their products in a very roundabout way, and then calling it free.
Usability costs. Ads are by definition content users didn't want but are receiving anyway. They use up the bandwidth of users. They take up space on the interface and distract the user, taking attention away from more important things. They make sites uglier and harder to use. They lower the signal to noise ratio.
Banner blindness. It's been proven that people have become used to ignoring banner ads. Their eyes jump over them as soon as they're recognized. Since there may be false positives, this habit has implications for user interface design: an actual user interface element that looks like a banner ad will be ignored by most people. On the other hand, sites have also begun to style their ads exactly like their main content in order to make it harder for users to distinguish them.
Oh yeah, I can't believe I didn't even mention some obvious ones like bandwidth usage, slower page performance due to loading and rendering and JavaScript-based trackers, etc. There are so many different things to enumerate.
