The Google Content Network (Google's ad network that includes over a million websites) connects Google's hundreds of thousands of advertisers with our 1 million publishers. Advertisers can control where the extra layer of control and complexity is added with our targeting options. Here are the ways an advertiser can show ads on your site.
  1. Contextual Targeting
  2. Placement Targeting
  3. Remarketing
Advertisers choose a particular targeting option depending on their overall goals. You might be most familiar with contextual targeting, which enables advertisers to choose broad themes that match the content of your site. For example, if I'm marketing my cheese shop, I create a keyword list that includes terms such as "cheese," "gourmet" "cheese," and "delicatessen," among others. This would allow my cheese shop ads to show up on sites about gourmet cheeses as well as next to content on other sites that mention gourmet cheeses.

At the same time, some advertisers are interested in showing their ads on specific sites because they find a match between the site's visitors and their offerings. They can do this using placement targeting; in general, advertisers who tend to be more brand-sensitive use placement targeting because they can choose the sites where they want to show their ads.

More recently, we've opened up remarketing, which enables advertisers to target ads to users they've previously interacted with, to all AdWords advertisers. At the same time, users can continue to control the ads they see by using the Ads Preferences Manager.

To help advertisers target your sites, we recommend ensuring that there's a clear theme to each of your pages, if you're going to allow for placement targeting, create sections of your pages that clients can target easily. Lastly, think about your site from an advertiser's perspective.