Google will search and scan your website and they will see if you’re writing on a bunch of different topics or if you’re writing on a specific topic. So if you write on many things, Google will not show you ads that are related to anything, so the CPC will be low.
If for example you have an authority website with many great quality articles on a certain topic like Dog training, and all your content is related to training your dog, then Google will show you more related ads about dogs, dog toys, dog training programs, dog products, insurance for your dog, etc.. these ads will, of course, pay more.
Contributor: Stephen Montagne from nethustler.com