When creating a new campaign for an advertiser, we generally suggest you structure your insertion orders so they include the following three types of line items, which roughly correspond to various stages of a purchase funnel.

Here are some suggestions of where you could use the different strategies available to us across the different stages of the funnel.

Upper Funnel
Prospecting line items are line items with very broad targeting that are used to discover which users are receptive to your ads.

Mid Funnel
Behaviourally targeted line items are line items with slightly more specific targeting that are intended to be used to refine your existing audience lists and discover new audiences that are similar to your target audience.

Lower Funnel
Remarketing line items are line items that use pixels—or Floodlights, if your advertiser uses campaign manager — to target users who have been to your advertiser's pages in the past.