When it comes to a program in diablo 3 you will have a few different options here are the most likely choices.
The first d3 program would be that of a macro or a bot. These are things players use to have the game play for itself. They could be simple programs that run from 2 different vendors, to more complex things that will actually go hunt, level, and farm items for you in the game. The range of macros and bots is vast and what they do for players is great as well.
The second would be a d3 hack. These diablo 3 programs would be things that alter the actual game itself. They might be a simple speed hack to move faster, or a complete teleportation hack that lets you move around the game instantly. Hacks most of the time do some sort of diablo 3 packet injecting that forces the game to give results that you would not be normally able to do if you are playing legit.
The third would be a diablo 3 addons. D3 addons allow players to improve their game experience and are normally allowed by blizzard. They might be a timer that shows a countdown on certain buffs you have in the game. So maybe a type of armor is about to run out well with an app it will display the actual count down timer for when it runs out. Another addon might be one that shows the exact amount of hit points of a mob above the mobs in the game. So instead of looking at their health in the top of the screen you can see the health bar right above their heads. Addons help make the game much easier to play. Diablo 3 programs such as this most players seek in the game.
The last would be a diablo 3 mod. Mods are normally visual tools in the game. They can be a nude mod that allows you to see all players naked, or one that gives you a different appearance for items and characters in the game. For example you might look like diablo while player the game. Keep in mind mods only display on your side and other players cant actually see you using a mod in the game.
