In a new post to his blog Gonzalo Ayuso shows an interesting use for the CouchDB tool - using it as a filesystem for cross-server handling of things like images or other binary resources.
One of the problems I need to solve in my clustered PHP applications is where to store files. When I say files I'm not speaking about source code. I'm speaking about additional data files, such as download-able pdfs, logs, etc. Those files must be on every node of the cluster. [...] CouchDb has two great features to meet or requirements with this problem. It allows us to store files as attachments and it also allows to perform a great and very easy multi-master replica system.
He shows how use two libraries he's created to connect to the CouchDB instance and, based on this structure, be able to insert the content - a text file in this case - pull it back out, get the meta data about it and even move it to another location in the structure.