It may seems that major key-value type of database like Cassandra, HBase, MongoDB somewhat overshadowed the newcomer CouchDB, the situation has shifted after the announcement of CouchOne and Membase joined venture in February, 2011. The merging service of CouchDB and Membase Server has made Couchbase the increasingly popular Open Source Key-Value Store. It is because with the unity of the services, Couchbase provides the developer the one-stop service via well-known Memcached protocol. It can connect the memory caching and persistence layers transparently.
Furthermore, the collaboration between Couchbase and NTT Docomo has recently been announced, Couchbase is now nevertheless exclusive, the one and only NoSQL database recognized by the enterprise.
We are keeping an eye on the development of CouchDB from now on.
Our company is working on developing Couchbase related services. Please feel free to contact atWare,Inc. for further inquires.