Is there any active "document-based" database projects using .NET or Mono? Something similar to CouchDB, SimpleDB, LotusNotes, etc... Prefer open source.
I figure the JScript.NET technology could be used for the Map and Reduce functions over stored JSON documents.
Have a look at nsimpledb. Also RDDB, Apache Jackrabbit, FeatherDB (a Java clone of CouchDB), StrokeDB, ThruDB, DataWasp, and M/DB. Wikipedia lists all of the above as Document-oriented database technologies. Some are .NET, some aren't but I hope these links take you somewhere useful.
I would like to add RavenDB to the list as well. Written in C# and while it is not a direct clone of CouchDB, it was heavily influenced by the project.
One of the great features of the project is a service and embedded solution. Meaning you can run it as a service on a server or you can run an embedded version within your application's process.
Right now, Windows is the only supported platform, but great strides have been made by Rob Ashton and Jérémie Laval in the past few weeks to get it to work under Mono and Linux.
You might also want to check out Divan, a C# library for accessing CouchDB.
