Google Signals
Google Signals is an optional GA4 feature that links session data to signed-in Google accounts where the person concerned has enabled ads personalisation. It supplies remarketing audiences for linked Google Ads accounts plus additional age and interest data that goes beyond plain cookie or device ID data. Google Signals has not contributed to counting users across devices in reports since February 2024.
In practice
In practice, Google Signals is enabled in GA4 property administration with editor rights or higher and can be restricted by region if needed, for example for countries with stricter data protection rules. Switching it on has to be disclosed in the privacy policy and tied to consent through the consent management platform: in Austria, section 165 para. 3 TKG 2021 attaches that duty to storing and reading data on the user's device, regardless of whether personal data is involved, while the GDPR continues to apply to the processing that follows. Since Google Signals was removed from the reporting identity in February 2024, the data protection thresholds apply less often in GA4 reports than before; in exchange, the earlier cross-device gain in standard reports is gone.