Sticky blocks
From MoodleDocs
Moodle1.6
Sticky blocks can be accessed from the admin page. It is a method of forcing a block to appear site wide. They can be configured for either courses or MyMoodle pages.
If you add a block which is already present in a particular course of MyMoodle page then it will result in a duplicate. Te sticky block will be non-editable whilst the duplicate will still.