Arguably the same definition of "advertising company" as Walmart, by charging those selling products in its store for placement, display ads, inclusion in promotional materials, etc.
Arguably not the same definition as ClearChannel, who will take money from anyone to make every drive in America less scenic by plastering them with billboards. (And who combine data from third parties to understand who is seeing which billboards when.)
Apple is a first party supermarket that lets sellers self-promote, Google is operator of third party billboards at scale that reaches and watches all the traffic.
That said, I agree with the thread above that Apple taking great pains to anonymize things like maps trips, while selling user searching priority wholesale to Google, is hypocritical.
TL;DR: I don't understand why Apple doesn't acquire Kagi, put Kagi basic in iCloud and Kagi Ultimate into Apple One, and go from there.