Google has recently published video describing the way Adwords work.
It shows how the bids are calculated and how the auction process works.
The most interesting part of it is that the quality score (QS) is calculated based on 3 main factors: primary CTR (approx. 60 %), than relevancy (approx. 30%) and landing page quality (10%).
Well, the problem is, what relevancy and landing page quality is?
The main theme here is that Google wants to make sure the user and the advertiser have both the best user experience.
As for landing page quality, the “Contact us” and “Privacy” links on the landing page are important. It basically says that you are not hiding anything, and you let the user know upfront how you will treat his/her private data.
The other important piece of the landing page quality is the clear page navigation and the whole page presentation. It must be clear, what the page is all about.
One of the interesting ways Google measures relevancy is measuring the time between the clicks on the ad link and back button. Basically, if the user clicks ‘Back’ on his/her browser too soon, the page (and the ad) was not relevant for the user, thus your ad is .
See the “Introduction to the Google Ad Auction” video.
