How do you differentiate between using a first-party customer list and third-party data when building a custom audience based on compliance and data management rules?

The key differentiation between using a first-party customer list and third-party data when building a custom audience lies in the source of the data, the level of consent required, and the compliance obligations. A first-party customer list consists of data you've directly collected from your own customers, such as email addresses or phone numbers gathered during transactions or through opt-in forms on your website. Because you have a direct relationship with these customers, you're responsible for obtaining their explicit consent for using their data for advertising purposes. This typically involves ensuring your privacy policy clearly states how customer data will be used and providing an opt-out mechanism. Before uploading a first-party customer list to Yahoo, you must hash the data (e.g., using SHA256) to protect privacy. Third-party data, on the other hand, is data collected from sources other than your own, often aggregated from multiple websites or data providers. When using third-party data for custom audience creation, you're relying on the data provider to have obtained the necessary consent from the users and to have complied with all relevant data privacy regulations. You are not directly responsible for obtaining consent for third-party data, but you must ensure that the data provider is reputable and compliant. You should also understand the data's origin and how it was collected to assess its reliability and suitability for your advertising goals. Some platforms may restrict the use of certain types of third-party data based on sensitivity or regulatory concerns. Ultimately, first-party data offers greater control and transparency over data usage and compliance, while third-party data can expand your reach but requires careful due diligence regarding data privacy and compliance.