Addons can be surprising little fellows, breaking out of the perceived boundaries of what is right and easy and giving us something more intelligent or behavioral. These, my friends, are the really special addons, addons that change some aspect of the game that doesn't really affect your character as much as it affects you.
Behavioral addons are all around us. DBM is a behavioral addon because it changes the way you react to situations through audio and visual cues. There are new interactions between you and the information that are not happening for your character in-game. What about Auction House addons that force you to conform to a series of clicks each time you hit town, further changing your behavior based on the way the addon works? Interesting.