I have done a variety of things with MongoDB that started with the adoption of this solution at one company. I was involved in setting up the cluster and then the monitoring, alerting, and backup process. Once all of the set up was complete, I was involved in writing some of the components that were responsible for fetching data from MongoDB.
We are now responsible for running the platform, so whoever wants to run MongoDB comes to us and we explain how we can deploy the cluster for their applications. At this point, we build a cluster in the servers under a UNIX account. The number of nodes in the cluster depends on the requirements of the application side.
Some of the use cases we have configured MongoDB for are desk-tooling and a payment card profiling project. We are currently working on a data exchange platform. We also have a couple of use cases in the pipeline for potential MongoDB clients who also need the MongoDB Ops Manager.