To track paid social contribution to ecommerce revenue accurately, you need three things working together: UTM parameters on every paid social link that are captured in your storefront at the order level, a cross-channel reporting layer that connects your Shopify or Amazon revenue data to your Meta, TikTok, and Pinterest spend data, and a primary performance metric (blended MER) that measures business-level output rather than platform-reported attribution. Relying on Meta or TikTok's native attribution to tell you how much revenue paid social drives is structurally inaccurate. Every paid social platform over-reports its own contribution by claiming credit for conversions in its attribution window, including purchases driven by email, organic search, or other channels. Accurate tracking requires your own data layer, your own attribution rules, and a business-level validation metric.