Customizing interaction, the front-end or other aspects of Mathematica manually or programmatically. This includes global or local options defined for notebooks and cells, new shortcut keys or hotstrings defined by InputAliases, editing system files (like init.m, KeyEventTranslations.tr, etc.) to modify the front end interface, or any other method to ease interaction with Mathematica.
Questions about customizing the front end (menus, notebooks, mouse-appearence, etc.) should have the front-end tag as well. If you want to introduce new mathematical symbols, expressions or typesetting, use the tag custom-notation instead. Customizing keyboard interaction should include the keyboard as well.
Useful links:
Example questions:
