Thanks to GDPR, big tech is phasing out third party cookies and advertising identifiers - the technologies that ad tech companies use to track our actions online, share data with one another and build profiles about us without our knowledge or consent. That is good news for privacy and transparency, but the ad industry is coming out with cookie ‘alternatives’ that still allow companies to share our personal data. The one that is gaining traction now is Unified ID 2.0 which uses hashed emails as a way of identifying users across domains and devices.