Good article. Guess I don't have input on what may be the world's most important invention, because as you pointed out with one building upon the other, I find it hard to pick one to stand on its own.
One thing I find amazing with advances in technology is always made the world smaller. Air travel over sea travel: not just with mobility of people but now you can obtain commodities from half way across the world much cheaper and faster. Once we could put things in orbit, what we could do with satellites enabled SOOOO much.
Thanks mountain for another great post that makes us think!