Are they kidding me? Typing rules have always been two spaces. I don't think I could even not space twice if I tried. I was a typist before the internet too.
Can I let you in on a secret? Typing two spaces after a period is totally, completely, utterly, and inarguably wrong.
And yet people who use two spaces are everywhere, their ugly error crossing every social boundary of class, education, and taste.*
You'd expect, for instance, that anyone savvy enough to read Slate would know the proper rules of typing, but you'd be wrong; every third e-mail I get from readers includes the two-space error. (In editing letters for "Dear Farhad," my occasional tech-advice column, I've removed enough extra spaces to fill my forthcoming volume of melancholy epic poetry, The Emptiness Within.) The public relations profession is similarly ignorant; I've received press releases and correspondence from the biggest companies in the world that are riddled with extra spaces. Some of my best friends are irredeemable two spacers, too, and even my wife has been known to use an unnecessary extra space every now and then (though she points out that she does so only when writing to other two-spacers, just to make them happy).
Yeah, CG, it's never gonna happen for me either. And I'm trying to get my book published and in working with editors and agents, I have yet to receive that particular criticism!
In the days of typewriters, if you know what those are, two spaces were used after a period, colon, etc.
Then, when word processing equipment became prevalent, because every byte takes up space, we learned to use just one space, to keep the size of the file down.
One space text is more difficult to read if it is an equally spaced format such as that of a typewriter. If it is a Word/Excel document it is more difficult because the spacing between letters is not equally spaced but is arranged by the softward and varies between letters within the word. So one space between sentences does not jump out easily and say "Hey, this is a new sentence and not a typo by a fat fingered oaf who accidentally hit a "period" key".
The choice of font also has an effect upon how the structure of the sentences appear. Some fonts do not offer enough distinction between a "comma" and a "period".
Considering all of the typos, misspellings, and butchering of sentence form by the current generation, I feel that acceptance of one space between sentences if merely turning a blind eye to their lack of discipline or conformity.
