It is easy to replicate a CouchDB instance to another, either as a snapshot or as a continuous replication process. In addition to hosting locally, you could replicate to one of the commercial CouchDB providers like Cloudant.

An Open Source project under the umbrella of the Apache Software Foundation.

Data is stored as JSON "documents" making them trivial for web applications to consume.

You can access and manage the entire database over the web. No need for specialized drivers or language-specific libraries or writing a separate API for your application.

It is easy for applications to subscribe to a _changes feed that provides notifications on database updates.

Although the data storage is schemaless, you can enforce a schema on your data by validating documents as they are inserted & modified.

"Views" into a database can be written in JavaScript (or CoffeeScript).

CouchDB works very well even when the network is physically partitioned

CouchDB is considered an available DMS according to the ACP theory of database management. As such it allows every client to always read and write.

CouchDB is mostly used in applications where a large amount of data needs to be accumulated and where data only changes rarely.