Dado que Mercado Ads Extended Network aumenta el alcance fuera de Mercado Libre, ¿cuáles son las métricas clave y los mecanismos de optimización para asegurar un ROI positivo en estas campañas externas?

The correct answer focuses on optimizing reach and frequency within a curated, brand-safe inventory, leveraging Mercado Libre's high-intent first-party audiences. This strategy ensures ads are shown to relevant users in appropriate environments, maximizing campaign impact and ROI by targeting consumers with validated purchasing behaviors even outside the marketplace. Focusing solely on clicks (CPC) without considering the ad environment is insufficient as it ignores ad quality and brand safety. Measuring only traffic to the official store within the platform misses the point of an extended network, which aims to reach users outside Mercado Libre. Using Mercado Pago's Fintech environment as the primary conversion space is incorrect; while related, it's not the core mechanism for optimizing external ad campaigns for product sales.