In the ElephantOnCouch every subclass of the superclass Doc is persistent. Inside the class Doc, there is an array called "meta" to store the document's metadata. Actually _id, _rev, etc. are also metadata, but I like the idea to separate the document properties (_id, _rev, _deleted, etc.) from the metadata stored by the application. I agree with the ones have suggested to add "_meta" property containing all the metadata, so we can avoid conflicts in case an application stores metadata prefixed with an underscore, like for example _type or _class. ElephantOnCouch for example uses those metadata (without the _ prefix actually) to store the document type and its complete class name, used to recreate an instance of the stored object magically. If a _meta property is introduced, is it possible, eventually to create an automatic procedure to migrate from 1.x to 2.0?
-Filippo
