Zero-party data refers to the voluntarily shared information by customers directly with a brand. It includes preferences, interests, purchase intentions, and other valuable insights. Zero-party data is crucial for ecommerce brands because it offers accurate, firsthand information directly from customers, enabling brands to personalize experiences, tailor marketing campaigns, and make data-driven decisions. It helps establish a deeper understanding of customer needs and preferences, leading to enhanced customer engagement, improved targeting, and ultimately driving business growth.