Permesso.be and WDM Belgium specialize in e-couponing as a strategy to boost sales, enhance brand awareness, and build consumer databases. They offer a GS1-certified e-couponing platform which includes mandatory consumer registration, personalized coupons, and comprehensive campaign management. The document outlines the importance of optimizing e-mail campaigns, consumer engagement, and data management to maximize Return on Investment (ROI) in e-couponing efforts.