I was referring to internet advertising, I should have made that more clear.

But it's the dirty little secret of most advertising: there's no voluntary feedback to prove (consistently, objectively) how effective your $$ are being spent.

The last thing a marketing company or media provider wants to admit is that any of their services are underperforming, or worse, turning off buyers.

Only a very small part of advertising is actually product promotion. Coca-cola spends $4 billion a year on ads, do you think it's because otherwise no one would know that coke exists?

It's true that advertising is a great way to promote a product, but its far from the only way. For many years now I've done what I can to cut all advertising out of my life and yet I still buy lots of things, including things I've never seen a single ad for.

If Coca Cola stopped advertising for a year, their sales would surely start trending down.

If you drink it now, would you stop?

Almost no-one can honestly answer this for themselves. I think the truth is likely: 'no, I'd still order a coke at McDonald's, I'd still pick a coke up from a vending machine if I'm thirsty. But if I'm buying a takeaway sandwich, I might not also get the drink. Or if I'm in the supermarket, I might just skip that aisle.'

I'm sure it's almost completely subconscious.

Yes, but not because advertising lets people know about Coke. The people who still know about Coke would be the same after a year, I imagine.

The mechanism of how advertising works seems to be not that. I think repeatedly brand exposure does something to the brain and decision making that we don’t fully understand.

Familiarity, I think.

Exposure breeds familiarity, which breeds desire, I think.

Even if all you hear is an occasional ad about the company, you might get curious and research them yourself.

[delayed]