So what kind of ads do you have to put up? That’s the good part—you don’t have to decide. Google does it for you. AdSense always delivers relevant ads that are precisely targeted—on a page-by-page basis—to the content that people find on your site. For example, if you have a page that tells the story of your pet fish, Google will send you ads for that site that are for pet stores, fish food, fish bowls, aquariums…you get the picture.
Yup! I always wonder how Google is able to know the content of a web page and generate relevant ads to match its content. Perhaps its due to the keywords being used.
Many factors that Google use for showing the ads on our sites... Contents, keywords, anchor text, description or even the caption of the picture... They have the great script for doing all of that! Amazing!