Please note that mods are created by people who know how to program in Lua and XML but only use functions that are allowed within the game. Considering many of these mods in the past have bordered on automation, Blizzard has significantly reduced the effectiveness of add-ons in this category, but some do still exist. They don't just tell you what's going on, they actually help you do it. Streamlining mods - All mods allow the player to do things more easily, but these mods actually let you *DO* things more easily.
Most very popular mods fall under this category. Healers often use a mod that allows them to better recognize who in the party is injured, for example. Most mods fall into one of a few categories: