[gnode]

The audience for non-individual web ads is not the entirety of Internet users. For instance, when I make a search on DuckDuckGo my geographic location (although this is optional) and search terms provide a demographic that is useful for specific advertising, without personally identifying or tracking me. Similarly, an online newspaper can include ads appropriate to the story viewed, and the geographic location of the user, without need for tracking.

[karljtaylor]

Facebook and Google (and nearly every other social ads platform that evolved along the same playbook) avoid the 'personal'by aggregating users above certain thresholds. It's fairly precise, and often the only times I can spot an individual is if they're flagging something geographic or contextual (e.g., search) that is unique. (for example, I know when my parents visit my blog because I know their network hostname and location.)

when you say, begin to search for trips to disney and start looking through photos on Facebook, it isn't that an advertiser discovers you, gnode, are looking for a disney trip, it's that the platform adds you to an audience of people interested in disney and to an audience of people who are interested in travel. advertisers engage with those audiences, platforms hold the data.