This document discusses why and how Visibiz is using MongoDB in their social CRM application. They chose MongoDB because its schema-free and document-oriented model fits their need to allow customers to extend objects like people and companies with custom attributes. MongoDB also enables scalability through replication and sharding. Visibiz stores data in MongoDB collections like "things" for core and custom objects and "rels" for relationships between objects. They validate data against JSON schemas before storage.