Performance Max (PMax) is a goal-based Google Ads campaign type that serves across all of Google's inventory, Search, Display, YouTube, Gmail, Maps, and Discover, from a single campaign. Instead of keywords, you give it assets, audience signals, and search themes, and its AI optimizes toward your conversion goal across channels.
How it works
You provide asset groups (headlines, images, video), a conversion goal, and audience signals, hints about who converts such as your customer lists, website visitors, or custom segments. Google's AI then decides where and to whom to serve across its channels. You steer it with search themes (phrases people use) and control it with negative keywords and brand exclusions.
Where it fits, and the catch
PMax is strongest as a complement to keyword-based Search, not a replacement. Its "black box" reputation comes from feeding it weak signals; given a clear goal, tight audience signals, and negatives, it becomes a controllable prospecting and competitor-conquest engine. We use it exactly that way in the three-campaign B2B setup.