What is Google Consent Mode v2?

Google Consent Mode v2 is mandatory since 6 March 2024 for websites using Google Ads + Analytics for EU visitors. It's not a consent replacement but a signal transport layer: your site's cookie banner (or CMP — Consent Management Platform) communicates consent status to Google. Four consent signals: (1) ad_storage — advertising cookies. (2) analytics_storage — Analytics cookies. (3) ad_user_data — sharing user data for advertising. (4) ad_personalization — personalised ads. Two modes: Basic: Google doesn't load at all without consent. Advanced: Google loads even without consent, but in "consentless" cookieless mode — anonymous pings, no UID, modelling to fill conversion data gaps. Important: Advanced Mode is NOT a consent-free loophole — if your site loads Advanced Mode before the cookie banner, it violates Tw 11.7a (placement of technology without consent). The AP made this explicit in 2025. For websites: CMP integration mandatory. Not using (default = no consent) leads to 70-90% conversion data loss. For consumers: if you click "Reject All" and still see data leak to Google Analytics — complaint. Test: browser DevTools → Network → check requests to google-analytics.com / googletagmanager.com under different consent choices.