Concordia is a structure- or syntax-oriented editor. It gives writers templates for nodes, with fill-out fields for standard information like headers, keywords, etc. Each node can be augmented with meta-information (attributes), not seen by the reader. This information includes authorization and approval messages, and writer's comments.
Concordia treats links as being bidirectional. The writer needs to know the outgoing as well as the incoming links for every node. Having a list of incoming links is important to decide how the node should be written so it could be understood by each reader arriving at the node, irrespective of which link was used to get to the node. This is called the rhetoric of arrival.
Concordia uses a generic markup language, somewhat like SGML, to separate structure from appearance on the screen. A book design database defines the visual aspects of each structural element. The writer can toggle between the writer's and reader's mode, in order to check what a node would look like, given a specific book design database.