The New York- and Palo Alto-based company generates most of its revenue by offering support, training, and consultation for MongoDB. Customers come from a wide cross-section of industries and include Foursquare, Disney, Viacom, eBay, Telefónica, and several governments across the world.
This helps to solidify MongoDB as the leading NoSQL database. Having used MongoDB myself, I can see why they were able to raise so much funding. MongoDB is fast, simple, and flexible.