I wouldn't say its doing anything behind a users back.. All it is is that if you have a text box then powerpoint can (it doesn't have to, it's only an option) make text smaller as you type to fit everything in. The alternative is that my text will end up stretching below the slide and i have to manually go and reduce the font size.

Well, to be honest good presentations shouldn't have so much text on them anyway.. but in my job we use powerpoint for everything, including project status reports. So sometimes our slides look more like word documents.. :-s

I wish i could use keynote.. heck, i wish i could use my mac at work! But alas, its a Dell, XP and ppt instead.