> That's because an advert is effectively an unasked-for imposition on my attention intended to benefit somebody else more than it benefits me
"Adverts" are a pretty incoherent category here. There are a lot of things that are technically advertising — placement of a product, or informational content about that product, paid for by some company's marketing department — that most people would never think to call "an ad."
For example, the end-caps in a grocery store? Ad space, auctioned off by the retailer each month!
But you're already shopping, looking for things you need, comparing brands; and these end-caps are effectively just putting things you might have been looking for anyway, where you'll find them sooner. So people don't tend to think of these as ads.
(They are ads, insofar as they succeed in getting many people to never go to the regular place in the store where that thing is, and therefore never doing a fair compare-and-contrast of the product to its alternatives, being swayed by alternatives that might be running sales, etc.)
But do they steal your time? No, in fact the opposite; if you pay attention to products on store end-caps at all, and ever buy anything from them, then they mostly will end up saving you a tiny bit of time. So consumers don't tend to perceive these as ads.
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Now take this one little bit further: sponsored search results. These sometimes feel like ads and sometimes don't.
If you think about it, sponsored search results are a lot like store end-caps... except that their existence makes the regular "store shelves" of the SERP page take longer to get to.
If they end up showing you the thing you were actually looking for (as they might if you're searching for a specific brand, and that brand has paid-for placement for their own name — perhaps to defend against others placing for their name; or perhaps they're bad at SEO and their website ranks badly in the organic SERPs for their own name) then these sponsored SERPs feel like they performed a genuine service for you.
Likewise, if they end up showing you something better than what you were looking for (as they might if the organic listings, ranked by SEO-ness, end up ordered askew to actual product value or popularity; while the sponsored listings, ranked by auction, end up ordered by, essentially, the paying company's stock price, and thereby by how much consumers already interact with them), then you also might come away pleased with the existence of these "ads."
But the other maybe 90% of the time, they look and feel and act like ads — things less-relevant than the organic SERPs, that you want to just get out of the way of the search — and so are perceived as ads.
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And now, consider, say, the catalog of other products available for purchase, that used to come in-box with products from some manufacturers. You'd buy e.g. a LEGO set, or a couch from Sears, and end up with a glorified flyer telling you about all their other products — often in much greater detail than you'd get by viewing the products in a retail store. (This has been mostly superseded by the existence of online stores and product unboxing+review videos — but it's still a good object lesson.)
Were these catalogs, ads? Maybe. Probably the majority of people who received such a catalog never ordered anything from it, and had their time wasted having to dispose of it. But because these catalogs were being sent to people who the manufacturer knew already had shown willingness to purchase from them, it's likely that a much larger percentage of people were "called to action" by these catalogs than by what you'd normally think of as an advertisement.
And, in fact people sometimes would just read this type of "ad" for fun: fantasizing about things they might one day own! (I recall doing this myself, as a child, with certain toy-brand catalogs)
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One more turn of the screw: is a movie or TV show that stands on its own as a work of entertainment, but which was made at least in part with the motivation of getting people interested in purchasing things from the franchise licensor's universe of branded products... an ad?
Certainly, back in the 80s, when advertising laws were more lax, and there were kids' cartoons running untrammeled with "integrated" advertising: embedding ads for the merchandise itself; showing the equivalent merch in the show; etc — there was every reason to call those shows "ads."
But is Hello Kitty and Friends (2020) an ad?
Now, if you said yes to that, try again with: is a Marvel movie an ad?
If you said yes + no: what's the difference? Prestige?