"Demographic Targeting allows a more granular approach to marketing goods or services based on a specific audience. Much like geo-targeting, marketers can specify and gear specific items, specials/coupons and ad content based on a specific demographic."
--Geoff Geiron, My Geek
With millions of potential customers online daily, it’s important to know how Demographic Targeting works to make sure that your ads reach a majority of the right customers.
Find specific market segments
The most widely used method of targeting demographics online -- on both ad networks and individual publishers -- is through the use of third-party research services like comScore, Claritas, and Nielsen//NetRatings.
On the individual site level, advertisers go directly to the research companies and use their data to identify sites with a high composition index of a certain demographic (for example, Oxygen.com has a high female index).
Or, by using an ad network, advertisers can leverage that research to target across different sites with one media buy.