GUEST OPINION: In a post-cookie and privacy conscious world, data clean rooms are one of the most discussed solutions within the ad-tech and mar-tech ecosystems. Legislation such as the EU’s GDPR (General Data Protection Regulation) and imminent changes to Australia’s Privacy Act, increasingly restrict how personal identifying information (PII) can be collected and shared. Therefore, creating a secure environment where data from different sources can be activated without revealing PII is highly appealing.