I bought a Dyson last summer. Amazon is still suggesting that I buy more vacuum cleaners.
'In that order?'
"Shhhh, just give us money."
Half-joking there -- in a previous discussion, the claim was that the ad-buyers don't care enough to check for whether these product-buyers were ones that had already seen an ad, or it was after the fact.
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).
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.
The key take-away should be that you're comfortable with buying household appliances online, usually not that you need another vacuum cleaner within the next year.
Banks and merchants and publishers and advertisers and all the layers in between create dozens of data silos and nobody is interested in sharing. Add to that the weird expectation that people don't want to be tracked but yet want adtech to know when you've bought something.
In general I think that all of the personal surveillance / categorization will end up being more truly profitable (as opposed to 'twinkie calorie' profits of ad networks) as they are used to suggest price points for products and services rather than to direct attention to products.
This happened to me just last week. Unfortunately, it's the least of Booking's user-hostile traits.
Like sending me e-mails pestering me to review a hotel I checked into less than an hour before.
Or flashing "Hurry! Only 1 room left!" when I know for a fact that the hotel I'm inquiring about is 90% empty.
Or flashing "23 people booked this hotel in the last 24 hours!" when I know the inn only has 4 rooms and is in probably the lest popular destination in North America.
Unfortunately, there's a particular place I have to travel to which only has one motel within 70 miles, and the only way to book a room in advance is through Booking.
They also don't update that fast.
You looked at a hotel in London and a certain hotel is the best revenue generator in the area - for a little bit you're going to see that ad... or maybe you're going to see that ad for a long time, if there are no better options to advertise.
I browsed retailers to copy the specs into my ad.
Hint to Amazon: not everything is a consumable ;)
I'm going to go with Occam's razor here: the advertisers are not scarily competent but instead typically bumbling and stupid.
