I’m going to start this post assuming you have already CREATED a model / library in Cognos Analyst and are familiar with Cognos Analyst models in terms of modeling and creating an application. Once the Analyst model / library is ready, the end users must be able to access the cubes, enter data, manipulate data and perform all manner of tasks. This is done via the web-based interface which is basically where contributor comes in. The Contributor Application is basically a published version of the Analyst model.
As a published model, it is different or enhanced from the model / library in the following ways:
Provides a web-based front-end to the end users to access the application(s)
e.List creation and maintenance (Analyst can use a dummy placeholder for modeling purpose)
Allows user access and security settings
Translations (or Aliases in Hyperion Planning jargon as far as I know)
Essentially the model from analyst is copied into a contributor application so the underlying structure is the same. The other options like security, e.List, data validations, etc. which are not part of Analyst are managed here and the application is made available to the end users.
The modeler or designer can continue to work on Analyst without impacting the published application until the changes are synced to the contributor application. Even then the changes are not reflected until the Development version is migrated to the Production version (a process that is known as GTP – Go To Production).