Yes, the explanation of typewriter vs. word processor is correct, and two spaces after a period are no longer needed. I'm an editor professionally, and I've had to relearn that one space is now correct.

And I have good news on the comma front for NoahsMommy: That extra comma (it's called a series or serial comma) in a short, clear list of items like your example is only "strongly recommended" by the style folks. It's only "necessary" if there is a chance that the series can be misread without the comma.