Power Editor is Facebook's bulk editing tool that allows marketers to more efficiently manage advertising campaigns. It provides advanced features like customizing bids, duplicating ads for testing, using tailored audiences, and extracting competitor data. The document outlines tips for using Power Editor like bidding strategies, bulk editing, advanced audiences, placement customization, and testing to optimize campaigns and reduce costs. Marketers are encouraged to start using Power Editor by creating test campaigns and learning from the results.