Among the new crop of NoSQL database products, MongoDB ranks quite high, in my opinion. The company that produces MongoDB is 10Gen, a venture backed new start-up since 2008. But its rapid growth over last 4 years bears testimony to its technical strength.
The other key tenet of MongoDB is its scalability architecture – it can scale out horizontally using its automatic “sharding” (or keyrange partitioning). It does provide master-slave or peer-to-peer replication for high availability, recovery, and performance. One of its customers Disney’s Interactive Media Group, for example, has 1400 instances of Mongo. It uses sharding for write performance and replication for read performance.
MongoDB can be deployed from the cloud via Amazon’s AWS. Their revenue model is via support services, training, and consulting. Partners include VMWare, Amazon, Redhat, etc. – all cloud platform providers offering MongoDB as an option to their clients. Although the database suits document storage the best, it can handle other unstructured data like video, and images. But initial thrust seems to be those customers looking for high scalability using commodity hardware and superior performance.
MongoDB claims over 400 customers, including many internet companies like FourSquare, Craigslist, etc. Several textbooks have been published on MongoDB and the development community is growing fast. It certainly bridges the gap between traditional RDBMS (Oracle, MySQL, SQL Server, DB2) at one end and Key-Value pair search engines (Riak, Cassandra, Voldemart,..) at the other end.