Have you ever lost a battle because you fumbled through a sequence of actions? Perhaps when trying to run from a rogue you dropped a Stoneclaw Totem rather than the intended Earthbind Totem. Alternatively, you may have cast Frost Nova rather than Counterspell on a Warlock casting her 1.5 second Fear. Missed clicks or keystrokes have been the bane of many players. This is where the magic of macros can save you from keyboard fumbling.
Among their many uses, macros can be used to establish cast sequences, "I win" buttons and evasive action commands.
Macros are something many players have heard of, but shy away from because they require some basic scripting knowledge. For the uninitiated, macros are commands built by users to execute customized actions or action sequences. A macro, known in the Computer Science world as a macro instruction, are defined as a rule that specifies how a certain input sequence should be mapped to an output sequence. Sounds horrible, I know, so let's make it easier.
Macros in World of Warcraft, are really just new and simplified ways to do the same old things. For a Mage, this can be a Presence of Mind / Pyroblast button, the "I win!" macro for Fire / Arcane mages. From simple commands to eat and drink at the same time, to determining a target's status (friendly or hostile) and casting an appropriate spell, macros can be used to streamline game play and clean up your User Interface.