- I buy product X online.
- AFTER buying it, I'm flooded with ads about the same product X.
- Why are they wasting money in this way - I think - I won't buy it again soon!

Suddenly a crazy idea strikes me:
The company running the ads, is able in this way to tie the number of ads impressions to me and to my purchase.
In some *superficial* statistics, I will be a guy who has seen thousand of ads AND bought a product. The kind of superficial statistics you show to CEO's

I'm the proof that the marketing company is running ads very well and deserve a good share.

More useless ads they send me the better for the marketing company, as it will justify higher expenses.

I think I also helped implementing this system on some website, unconsciously.

It's just that I have a perverse mind, or did I find how to be rich?