If you want ads shown only to people who already visited your site, Performance Max is the wrong campaign for it. Google calls PMax audience signals "audience suggestions" and says PMax may show ads to relevant audiences outside them. Add your website visitors as a signal and PMax treats them as a starting point, then goes looking for new people too. For pure YouTube retargeting, we build a Demand Gen campaign with optimized targeting switched off, so it stays on the list you chose.
What we saw on the call
On a mentoring call, we opened an advertiser's PMax campaign. They had added video assets to it, and the goal was YouTube retargeting. Under signals, the audience was all website visitors from the last 90 days.
We called it a fundamental flaw. PMax uses that list as the initial signal, then goes out of that audience and shows ads to newer people. That isn't a setting they had missed. It's how PMax works.
So we rebuilt it as a Demand Gen campaign while still on the call. Channels: YouTube only. Audience: the same website visitor segment, which showed an estimated size of 5,100 to 22,000 people. Then the step that matters most: we unticked optimized targeting. As we put it on the call, that's how you get pure remarketing ads on YouTube.
What Google says about each campaign type
- Performance Max. Google's audience signals page says adding signals is optional, calls them suggestions that guide its AI, and notes that PMax "may show ads to relevant audiences outside of your signals" when they have a strong likelihood of converting. Google documents no setting that keeps PMax inside a signal. Even PMax's re-engagement settings are described as bidding higher for lapsed customers, not as limiting the campaign to them.
- Demand Gen. Google's setup steps for the ad group say you can keep or deselect optimized targeting. Its optimized targeting page says the feature looks beyond the audience segments you selected, is turned on automatically, and can be turned off in ad group settings. Google's own example for reaching previous customers is manual targeting only, with optimized targeting off.
- Demographics too. With optimized targeting on in Demand Gen, Google says demographic expansion also applies, so the campaign can reach beyond the age, gender and other demographic selections you made.
Where PMax still fits
This isn't an argument for Demand Gen as a way to find new demand. It's a narrow job: putting a video in front of people who already know you. On the call, the advertiser also floated a lookalike version as a later test, run as a separate campaign. Demand Gen supports lookalike segments, but keep that test apart from the retargeting campaign so you can see which one did what.
If what you want is new people who resemble your visitors, PMax's expansion is the point, and then the quality of the hint matters. On a separate call, we reviewed an ecommerce brand's PMax campaign whose signal hadn't been edited in two years, with website visitors as its only first-party data. Our advice was to pass customers and people who had added to cart instead, so PMax looks for people like buyers, not like everyone who landed once. Our Performance Max guide covers signals in full, and in our experience a custom segment built from competitor URLs describes the buyer better than broad interest audiences.
The takeaways
- PMax audience signals are optional suggestions. Google says PMax may serve outside them.
- There is no documented way to lock PMax to a website visitor list, so it can't do pure retargeting.
- For YouTube retargeting, use Demand Gen, choose YouTube, add your visitor segment and turn off optimized targeting.
- If you do want PMax to prospect, feed it buyers and cart data, not all website visitors.
Common questions
Can you do retargeting with Performance Max?
Not pure retargeting. You can add website visitor lists as an audience signal, but Google says audience signals are optional suggestions and that Performance Max may show ads to relevant audiences outside your signals when they are likely to convert. Google documents no setting that limits a PMax campaign to a remarketing list.
Do PMax audience signals restrict who sees my ads?
No. Google describes audience signals as suggestions that help its AI optimize toward your goals. They guide where Performance Max starts, but Google says the campaign may reach relevant people outside the signals if they have a strong likelihood of converting.
How do I show YouTube ads only to my website visitors?
Create a Demand Gen campaign, select YouTube as the channel, add your website visitor segment as the ad group audience, and deselect optimized targeting in the ad group. Google says optimized targeting looks beyond the segments you select and can be turned off in ad group settings.
What does optimized targeting do in Demand Gen?
Google says optimized targeting looks beyond your manually selected audience segments to find people likely to convert, using your segments as signals. It is turned on automatically. When it is on in Demand Gen, demographic expansion also applies, so ads can reach beyond your selected demographics.
Can PMax customer retention goals target only past customers?
No. Google lists re-engagement and high value re-engagement as Performance Max settings that bid higher for lapsed customers. They need value-based bidding and a Purchase conversion goal. Google describes them as bidding higher for lapsed customers, not as a way to limit the campaign to existing customers.