As of December 13th 2018, advertisers now have the option to pay for conversions, rather than clicks, when using Google Display Campaigns. This means that you will only be paying when customers convert on your website or app, while never paying above your target cost-per-action (CPA).
The Google Display Network (GDN) has a growing list of ways to reach potential customers. To do so, we can target audiences (in-market audiences, affinity audiences, demographics, etc.) or content (topics, keywords, etc.). To take that a step further, we can layer different types of targeting to truly pinpoint a subset of users or we can simply observe how different types of people interact with our ads. This is where the very important distinction between targeting settings come into play.