Google only wants to show ads that people will want to click on and are relevant, or they are wasting their own revenue by wasting the display slot.
And one (but definitely not the most important one per your point #1) is how much someone is willing to pay for the slot.
If you’re paying $100/click, but no one ever clicks on it because it isn’t relevant (like trying to sell real estate to someone trying to find used computer parts or whatever), they’ll still not show the ad.
And one (but definitely not the most important one per your point #1) is how much someone is willing to pay for the slot.
If you’re paying $100/click, but no one ever clicks on it because it isn’t relevant (like trying to sell real estate to someone trying to find used computer parts or whatever), they’ll still not show the ad.