The company, Postmark, has successfully migrated its activity feed from MongoDB to Cloudant, a NoSQL database service provided by IBM. The migration was necessary due to performance issues with MongoDB and the desire for a more scalable solution. After evaluating several options, Postmark chose Cloudant for its ease of use, high level of customization, and excellent support. The migration process was not without challenges, including a major issue with RabbitMQ queues and a delay in importing data into Cloudant. However, the team was able to overcome these obstacles and is now enjoying a stable and consistent system. The new setup allows for better scalability, improved performance, and more efficient handling of email activity and search. With the migration complete, Postmark can now focus on implementing new features, such as Open Tracking and Link Tracking.