How do you find the sites that your target audience is using? Google Ad Planner offers a good place start.

Ad Planner makes it easy to define your target audience using filters like gender, age, household income, education, and location. There is a convenient list of pre-defined audiences which you can select. In addition you may add ’sites visited’ or ‘keywords searched’ into your audience filters. As you ad or change filters, the list of suggested sites updates automatically. According to Google, the data used to drive the matching system comes from “a variety of sources, such as aggregated Google search data, opt-in anonymous Google Analytics data, opt-in external consumer panel data, and other third-party market research”.

Once your audience definitions are in place, it’s time to set some site filters. The site filter allows you to restrict your search to sites that accept advertising (of any form), or to sites within the Google Content Network (or both, or neither). You may also choose to see only sites from specific categories (you can choose multiple), as well as domain extensions. From there you can further refine your site selection by the type and/or size of ads they show.

With your filters all set, you should have a sizable list of sites that Google deems relevant to your target audience. What we’ve found, however, is that these lists tend to favor large, heavily trafficked sites. In some cases that is exactly what we’re looking for, but it’s often the case that we would prefer to find smaller, more niche sites. While it is likely that highly educated females between the ages of 25 and 54 who are in the medical field do visit usnews.com, a whole lot of other people do too. We need something a bit more focused.

One way to bubble up the niche sites is to sort the list by the Comp Index. The Comp Index reports the concentration of your selected audience relative to all users in your defined country. The higher the comp index, the more likely that an ad impression on a given site will be seen by someone in your target audience. The list can be sorted in a number of ways by clicking on labels across the top of the sites list, but there are also 3 preset sorting arrangements that are available in the upper right corner where the number of results is listed. Experiementing with those might reveal some winners.

From here you can pick and choose the sites your think are most valuable and then save your list into a media plan, or export the results to a CSV. You can also visit sites in the list, or expand listings to get more info. This is sometimes a good idea because the categorization is not always perfect. For example, a recent list we pulled up contained the site Mainstreet.com, a news site with a focus on business and financial stories. Google had it listed under “Astrology & Divination”. Close, but not quite.

So now you have a good idea of where to find your audience. All you have to do is get there.