When implementing dynamic remarketing, what data layer variable structure is essential for accurately passing product-specific information to ad platforms?

For accurately passing product-specific information to ad platforms in dynamic remarketing, a structured data layer array called 'ecommerce' containing a nested 'items' array is essential. This 'ecommerce' object serves as a standardized container for all e-commerce related data. The 'items' array then holds individual product details as objects. Each object within the 'items' array represents a single product and must contain key-value pairs for properties like 'item_id' (the unique product identifier), 'item_name' (the product name), 'price' (the product price), 'item_category' (the product category), and 'quantity' (the quantity of the product involved in the event). These properties are crucial because ad platforms like Google Ads expect specific, well-defined attributes for creating dynamic ads. For example, a product view might push this to the data layer: dataLayer.push({'ecommerce': {'items': [{'item_id': 'SKU_123', 'item_name': 'Red T-Shirt', 'price': 25.00, 'item_category': 'Apparel', 'quantity': 1}]}}). Ad platforms use the 'item_id' to match products viewed on a website with products in their catalog, 'price' for displaying the correct cost, and 'item_category' to tailor ad content. The 'ecommerce' object should also include an 'event' key defining the event type, e.g., 'view_item', 'add_to_cart', or 'purchase'. Without this standardized 'ecommerce' structure with the nested 'items' array and required product attributes, ad platforms cannot correctly ingest and utilize the product data necessary for dynamic remarketing campaigns, leading to inaccurate or ineffective ad targeting.