Offline capable peer to peer replication was the main reason I chose CouchDB - we needed something that would realistically run on clients, even mobile devices.

Offline capable peer to peer replication was the main reason I chose CouchDB - we needed something that would realistically run on clients, even mobile devices. NoSQL we mainly chose because we needed schema-less data (the whole system relies on ad-hoc design updates). It's basically an information system IDE with rapid application development.