This is a very interesting article. Although I learned to type on a manual typewriter (with blank keys, no less) in high school in 1962, I made the leap to using a single space after periods around 15 years ago. Our church secretary, who is in her early 50s, uses two spaces. I edit all our church bulletins and have been tempted to use a global replacement to change double space to single space, but I just leave well enough alone. One might think that because of our ages, the opposite would be true.