A bit more on the mechanics of how this works...
You buy a product from "PRODUCT COMPANY A" and somewhere along the way, that company has a "ping graphic" from "AD COMPANY B" on several pages
throughout their site. Based on your browsing habits on the "PRODUCT COMPANY A" site, and their specific relationship with the ad company, "AD
COMPANY B" can be aware if you viewed the online catalog, signed up for emails, or even made a purchase.
"AD COMPANY B" doesn't know who you are when you make a purchase. All they know is that some random number (maybe "USR.0012974774.NXG" or
something) that represents your computer made a purchase on the website of "PRODUCT COMPANY A" within the past 30 days, or whatever other timeframe
they want to apply (usually 30 days).
When you leave the website of "PRODUCT COMPANY A" and head out into the wild of the Internet, their agreement with "AD COMPANY B" would stipulate
the conditions upon which you receive a preferred or premium ad. In other words, "AD COMPANY B" will deliver a high-paying ad for "PRODUCT COMPANY
A" when you visit "WEB SITE C" if that site is displaying ads from "AD COMPANY B." And, they will pay a premium to make sure you get their ad,
over all other possible ads in the inventory.
---WHO KNOWS WHO---
There is no interchange of data. "PRODUCT COMPANY A" has no idea you visited "WEB SITE C" or "WEB SITE D" or "WEB SITE X," only that "AD
COMPANY B" is charging them for each time you see one of their ads.
"AD COMPANY B" is aware of the sites you visit, but they don't have your personal data that you provided to "PRODUCT COMPANY A" unless you
specifically provided it, or one of them broke the law.
"WEB SITE C" has no idea you bought something at "PRODUCT COMPANY A" and unless "WEB SITE C" is serving the ads themselves (very rare these
days) has no idea you're getting their ads (unless you start a thread
). Also, there is no exchange of available personal data between "AD
COMPANY B" and "WEB SITE C" as the ads load in "browser-time," or after the servers of "WEB SITE C" send the pages to you.
"WEB SITE OWNER G" is wondering if that made sense for "WEB SITE USER M?"