Google AdWords as of recent declared changes to how it will target ads beginning on January 18, 2017. From that date forward, all ad groups with no targeting method selected will naturally be qualified to show ads through the entire Google Display Network (GDN).
Ads with no targeting method chosen will simply get served to anybody. At present, ad groups with no targeting set up don’t get served by any means. All together for an ad group to be served all through the GDN, customers need to focus on their campaigns considering topics, keywords, as well as group of audiences.
This is going to take place, however fortunately you don’t need to do anything to plan for it. Google is not going to pull a quick one and begin serving non-targeted ads without a customer’s approval. Google is going to naturally stop any ad groups or campaigns you’ve made that are not targeted.
In any case, going ahead you should be wary about targeting any ad groups you create, because after January 18th Google will push them out regardless of whether they’re targeted or not.
Current display and video ad groups that don’t have a targeting method will be paused beginning January 18th, 2017 to guarantee they don’t demonstrate ads you don’t plan to appear.