This type of "trust us, we know what we're doing" targeting is typically less cost effective for advertisers. The fact it works at all is a technical achievement to be sure, but as far as Google goes I can vouch for the OP.

Well, if you are doing direct response advertising, you can mark (with utm source) and measure any kind of performance metric (CPA, average purchase price, whatever you can come up with), and if their clicks are not cost effective, you can stop buying them.

And if you do branding... branding is hard to measure anyway.

Note -- I'm not affiliated with google in any way, I just think their offering makes a lot of sense.

It depends what sort of business you're running.

If you're selling a product that's available nationally and appeals to a reasonably big demographic, you might not care much about targeting.

But if your business only supplies weddings in New York, then impressions/clicks by people who aren't planning a wedding in New York are largely worthless.

But the initial intent still has to be there. If I sell shampoo noone's gonna see my shampoo PPC ad just because they email a friend to say they've got dry hair. They have to search for a shampoo-related keyword I'm targeting.

And then once I buy shampoo,Amazon can make a deal with the Shampoo manufacturer to send a branded Amazon Dash button for repeat purchases.

If they have an Alexa device, Amazon can get shampoo manufacturers to pay to be the default choice when someone says “Alexa, order more shampoo.”

Not everyone wants to sell their soul. I'd pay extra to not get any of that.

In the aggregate, random posters on HN don’t matter. Enough of the world doesn’t feel that way to make Amazon a very successful company...