The text discusses a new feature being tested by Google in its Performance Max campaigns, which allows advertisers to opt in or out of Search Partners and the Google Display Network. This is significant because it provides advertisers with a level of control that was not previously available, allowing them to better align their ads with their campaign objectives. The article highlights the importance of this update for advertisers focused on efficiency metrics like ROAS or CPA, as it allows them to test whether excluding certain networks can improve performance. The feature is currently in the Alpha stage, meaning it is only available to a limited number of advertisers, and there is no information on when it might be more widely available. The update was initially spotted by a PPC Growth Strategist on LinkedIn.