"Ad Manager is not delivering ads for affected users" is definitely a reasonable title, I am also curious on why it was changed into a vaguer title (which is very likely a mod edit).
Google is soft-balling the impact of this, and I think the watered down title doesn't do it justice. Google's ad server is behind nearly 90% of all ads served outside of the walled gardens, and the ad server has been down now for 3 hours.
But because the ad server is a part of GAM, and their UI and reporting are still up, they can call it a partial outage.
