What is Custom Bidding in DV360?
In the image, a use case where the Custom Bidding optimizes for weighted conversions with different floodlights.

Custom Bidding was rolled out in DV360 this year. Custom Bidding enables advertisers to create an algorithm trained to optimize the bids for the highest impression value or the specified goal impression value.
Custom Bidding works with Google Analyics goals, custom floodlight variables, floodlight sales revenue, weighted conversions with different floodlights tracking activities, or performance indicators such as viewability and video completions.
According to Google, Custom Bidding doesn’t work with YouTube, Gmail, Twitter, Audio, Tag Guaranteed, or Programmatic Guaranteed inventory.