The CMIS API project aims to provide a generic API for integrating with CMIS compliant Enterprise CMS systems. Vendor specific modules, such as the Alfresco CMIS module will use the API to enable content sharing with specific repositories. This is a joint effort between Optaros, Acquia, and Alfresco.
This module does not provide any end-user functionality on its own and should be used in conjunction with other modules that require it, such as the Alfresco CMIS module at http://www.drupal.org/project/cmis_alfresco.