Yes, “different type of targeting” means you can still do targeting. Just not user-specific targeting. In many situations contextual targeting is actually far more effective (e.g., search ads have performed incredibly well even prior to much use of personal user info/history, because keywords searched at the time of search represent by far the most valuable piece of information to select the highest expected value ad).

Nope. Content-based targeting (e.g., AdWords, originally) doesn’t need to know anything about the user.

> “Didn't know you could use a portion of the dataset and expect approximately what you'd get with the whole set”

See: sampling

Once it’s up and running, I’d be surprised if there were as many typical factory jobs from this sort of work to form a union as some might expect. I get the impression semiconductor fabs are highly automated. It’s not like workers are laying down and connecting those transistors by hand.