But... how much waste have they introduced as well? I think a lot of old 'water cooler' talk may have been amplified by IM, solitaire, email, etc - much harder to visibly detect the amount of waste introduced by these technologies, although I'm sure they've saved a lot as well.

Sure, but now I don't have to go to the water cooler. Talking about a movie with the coworker down the hall is now a parallel process that takes maybe two minutes of total typing time, and while I'm not typing at him, I'm working on other things.

Compare to the water cooler, where it might take me a whole minute just to walk down there. Then we sit around and shoot the shit for maybe five minutes. Total time spent, let's call it seven minutes during which nothing got done except some simian grooming.