Adwords: Quality Score & Ad Rank Explained
Advertisers bid on target keywords that are relevant to their products or services. Bidding starts when a user conducts a search. The AdWords system then finds all ads that match those keywords and competing advertisers are pitted against each other. In a normal auction, the highest bid would win but ad positions aren’t just solely based on who bids the most. Other factors such as ad relevance and quality are also considered.