You can either join an advertising agency that specializes in Facebook media buying (e.g., Marketing Partners | Facebook Marketing Partners) or work at an early stage/mid-sized startup that focuses on paid social acquisition. Former – You get to know a wide spectrum of industries/verticals and build up client skills. Each and everyone of them has a different KPI like cost per engagement, cost per acquisition, cost per lead, etc… Latter – You can see the entire funnel from top to bottom, own your outcome, and work across different departments like engineering, creative, and analytics.