I'm not sure I agree. I mean, I see the theory you're getting at, but the Dyson example is built on a few assumptions we'd need more data on -- starting with the notion that Dyson owners are disproportionately more likely than owners of other vacuum cleaners to have second homes. And even if they do, that's, well, one more sale at most, and one that's more likely to be influenced by their experience with the first Dyson rather than ongoing advertising. When you say that you buy repeat items as gifts because they turned out well, you're tacitly confirming that further advertisements for that product aren't necessary to reach you. At best, the ads can sway you if they happen to be running an unusually good deal on the product you've already decided you want to buy.
The big problem targeted ads have now is, as other people have pointed out, that they seem to be targeted with knowledge of what you've recently been looking to buy, but not knowledge of what you've recently bought. If I search for polo shirts, I'm in the market for polo shirts, but once I buy polo shirts, I'm probably not going to be in the market for them for a few months. Once I buy a car, or a television, I'm probably not going to be in the market for another one for years.
I'm one if those "advertising doesn't affect me" people. Except, then I realised that advertising acts subconsciously and uses human psychology against us, and I'm not as immune as I thought.
I buy a Dyson, every ad I see for vacuums is a Dyson, it confirms I made the right choice, everyone is buying them, they're everywhere, etc.. Everytime I see a shiny new vacuum it's a chance for my brain to compare it with the old rubbish one; why are all those people "enjoying" vacuuming when I have to suffer it.
With polo shirts it's like "these new ones look smart/fashionable/etc." vs the old one.
Yes there is likely a lag in "this person was looking for ..." signals; but I still don't buy (heh!) that as _entirely_ silly.
>Once I buy a car, or a television, I'm probably not going to be in the market for another one for years. //
Car, probably, depends on the person's wealth; TV, I've v heard people say "we liked it so much we got another one for our bedroom" or whatever.
FWIW I'd never buy a Dyson ...
It's not as silly as it seems.
I buy repeat items as gifts (I like this, X will like this), or for my parents (home stuff), or when I bought something for one child I know and it turned out to be well made and now another child needs/wants one; or tech stuff that turned out well when someone else needs the same repair (eg new HDD).