MongoDB and MySQL are being used together in hybrid deployments to address varying needs of modern applications that require both structured and unstructured data management. Sage Group has integrated MongoDB into its ERP solution for midsize companies, while OpenSky has utilized MongoDB's flexible document-based data model for modeling a cross-industry product catalogue. In contrast, Craigslist migrated their massive archive of classified posts from MySQL to MongoDB to accommodate changes in schema without affecting performance. These examples demonstrate how hybrid deployments can provide the best of both worlds and offer flexibility for modern applications.