There are 8 different ways to target ads running on the Google Display Network (GDN). Each display ad targeting option is based on either the content (keywords) of websites across the GDN, or the behavior of traffic that transits the GDN.
To plan display ad targeting for a campaign, we first determine which of the 8 types of targeting are likely to be successful: (1) In-market, (2) Placement, (3) Affinity, (4) Custom intent (url, or keyword), (5) Customer list matching, (6) Topic, (7) Demographic, and (8) Remarketing. Compound, hybrid, and negative audiences further expand the flexibility of targeting.
A significant degree of experimentation is normally required before arriving at the best performing type and configuration of audiences display campaigns.