Harmoni provides basic services to Segue, Concerto and MiddMedia such as authentication, authorization and repository access using O.K.I. open service interface definitions (OSIDs).  This means that the same services are used to get the content of a Segue site as are used to get the assets in a Concerto collection or audio or videos from MiddMedia. 

This service-oriented approach simplifies application lifecycle management by abstracting out common services into a single codebase.  Thus when better repository management tools become available, Harmoni can be updated to use these and all applications that rely on Harmoni will benefit.  This approach also makes it easier to get these applications to interoperate since they already use the same services.  Contrast this with most other web applications such as Drupal, WordPress, MediaWiki etc which each have their own particular methods for authentication, authorization and storing content.