Buying something because you saw it in ads is a wrong choice. If you need something, it is better to make an objective comparison and choose the product with the best properties. I think that for a rational buyer ad should be worthless.
Product makers don't want you to make a rational choice though. For example, take speakers: cheap ones do not have a response curve published at all (so assume worst), and more expensive ones often have a small blurred graph that is averaged to an octave, doesn't show the deviation between different samples of a product and is only for on-axis sound.
And guitars have no spec regarding sound at all except for trivial things like scale length, weight etc.
Literally every source of information that lets you know about the existence of a product is, by definition, an ad. How do you make a rational decision about something you don’t know exists?
Hobby forums? I've been blocking ads for 20 years so it's difficult for me to imagine someone using an ad to learn about anything they want to be even slightly informed about. The main thing "sponsored" links or information tells you is that the thing you're looking at is trying to scam or manipulate you. If you want to actually learn about something and find good products, you look for people who are interested and knowledgeable in that area.
That's so obviously false. There are wikipedia pages about products, and they are not ads, either by definition or extension or induction or by anything. You don't know what "ad" means.
Maybe look up the actual definition of a word before talking about what it means by definition.
Was Wikipedia your first exposure to some product you previously didn’t know existed? Your “counterexample” makes no sense. Also, I’m pretty sure I make more money from advertising than you do, so I’ll stick with my understanding of what it is, thank you very much.
Before you look up something on wikipedia, you need to know that it exists in the first place.
You go to an imaginary price comparison website, choose "speakers" for example, and see all the kinds of products that exist. What do you need an ad for?
Don't you see "sponsored" products at the top? But I agree not everything is an ad, just most of stuff.
Is the wikipedia page a about eg. Coca Cola an ad?
Did you not know what Coca-Cola is before you read its Wikipedia article?
You could find the link to the Coca-Cola page at some other page, for example, "Dangerous chemicals".
I learned about products from different non-ad sources (HN, personal blogs, maybe even wiki). What's your point?
If you saw a product in an ad, but aren't aware of any alternatives because you didn't see ads for them, that kind of limits your choices.
The best concert I ever saw was one I wouldn't have known about if I hadn't caught a TV commercial for it the week before.
A moderately intelligent adult can understand that ads are biased and can separate the fact from the opinion. I want to know if there's a new pizza place that opened near me, that's a fact. I can resist taking their claim that it's the best pizza ever at face value. I don't need to fear it.
Advertising contains information. We can own the responsibility for deciding which information is valuable and which isn't.