Never Put Two Spaces After A Period – Business Insider.
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).
What galls me about two-spacers isn’t just their numbers. It’s their certainty that they’re right. Over Thanksgiving dinner last year, I asked people what they considered to be the “correct” number of spaces between sentences. The diners included doctors, computer programmers, and other highly accomplished professionals.
Everyone—everyone!—said it was proper to use two spaces. Some people admitted to slipping sometimes and using a single space—but when writing something formal, they were always careful to use two. Others explained they mostly used a single space but felt guilty for violating the two-space “rule.” Still others said they used two spaces all the time, and they were thrilled to be so proper.
Read more: http://www.slate.com/articles/technology/technology/2011/01/space_invaders.2.html#ixzz2sjI4n4vN
Booker's Blog 
Sorry, I know about this, and think it is absolute twattle. The extra space allows for a needed pause in between sentences.
Hi Chet, thank you for taking the time to respond. Not to be disagreeable, but to still disagree, I think it is correct, and as somebody who does newsletters, it can also result in fewer things referred to as “lakes” and “rivers.” The period is the indicator of rest. Not the spaces after it.
Hey David,
We have agreed to disagree many times over the years. This is not a problem to me at all, and I hope it is not to you either. Re the post to the other respondent, it’s not too late for you to learn how to type properly with all four fingers and two thumbs instead of what ever you meant by limited typing skills. Now, THAT will save you some time, I swear! All it takes is practice and you will be flying over the keys at lightening speed. All the best.
Chet
Yes, but think how much time I will save using all my digits AND only one space after a period. I could have it all written before I started.
Now you’re a comic. Good one. Made me smile.
I know the world is moving away from the two space rule, and I mourn it like a lost loved one. I don’t know why, exactly. I regularly write in AP style, and I can easily write with one space between sentences. But throw me into any other kind of writing, and I’m constantly battling the extra space. Oh, the drama! 😉
Hi Adria, thank you for taking the time to comment. I am old enough to have done it with two spaces, but have found it much easier on my limited typing skills and my mind not to have to remember that. One and done. That I can remember.