The Share web application has a special page called Dashboard, which contains windows of content called dashlets. Currently most of these dashlets are Surf dashlets, and it is possible to modify the contents on them. For more information on Surf Dashlets, see Surf Dashlets.
The preferred way of modifying Surf dashlets is by using Surf Extension Modules to target the component that should be replaced or hidden. It is also possible to add components to a dashlet this way. The Extension Modules section has all the details.