What are O&O and OA?
O&O is owned and operated, where you actually own the audience. In the simplest case this is like YT or Insta for Google and FB but it can be kinda nuanced with more traffic falling under the umbrella than you’d think. More and more this is where energy and attention is being focused, especially as cross-site data becomes scarcer.
Google has search, maps, gmail, youtube. Facebook has its social media sites, Amazon has amazon.com, Yahoo has its own sites. Bigger publishers with enough scale also run their own ad infrastructure, for example Washington Post has some of the most advanced in-house adtech.