I learned to type on an old-fashioned carriage typewriter, the kind you had to put two sheets of paper in to protect the roller and the key heads. And I was taught to always put two spaces after a period.
Once I started working in graphic design, it took my Creative Director about one month to break me of that habit, and now it is one of my biggest bug-a-boos. Computers recognize periods and compensate by putting enough space after them that the two spaces are not necessary.
Well, by the time I was in middle school (where I took typing class, which by then was called Introduction to Computers), we were using computers with MS Word, and they still taught us two spaces after a period. However, when I started taking journalism classes in college, they taught us to use only one space. In journalism, every space counts, and by eliminating the second space after a period you can squeeze in precious extra words. I get in that habit and it tends to spill over into everything I write. However, I'm pretty sure that most people still expect two spaces after a period in any document that isn't space sensitive. None of my professors or bosses (other than those involved in journalism) ever told us to use one space rather than two. I think it's evolved to the point where either is acceptable, but neither is truly right or wrong. If anything, two spaces is still prefered except in space-sensitive documents.
Annie
