Since AEM 5.6 there is a new WCM mode called Analytics. It is enabled after providing a SiteCatlyst framework for the project.
API documentation says (and this is the only information I could find about that) : "WCM UI elements are visible which are analyzable."http://dev.day.com/docs/en/cq/current/javadoc/com/day/cq/wcm/api/WCMMode.html#ANALYTICS
However I don't understand how it works and what it is for. It looks just like a preview mode for me. Can someone explain a difference? I would be very grateful.