I really don't mean to be argumentative, but I don't see anywhere in that link that it says water is a source of corrosion. It says that condensation occurrs, which can be a problem, but condensation and corrosion are two very different things. Corrosion is permanent, condensation is just water vapor in the air that has been cooled and thus become denser, forming water droplets around the cold. Rust would be the result of slightly acidic water on a metal for a long period of time. Some metals like stainless steel won't corrode from water though and others (aluminum for example) are less corrosive than others (steel, iron) when in contact with water. However, distilled water (or pure, non-acidic and non-basic) is right in the middle on the pH scale, meaning that it will not corrode.
I have run dry ice on my DFI/AMD setup a couple of times and am getting ready to do it on my Intel setup. Condensation definately does occurr, but not corrosion.