One thing I’ve noticed on the Internet ,is that on many message boards and blogs ,and occasionally email ,people often leave a space before a comma ,not after. I’ve never encountered it in handwriting ,typed and printed correspondence ,or any other media. Why is this practice so prevalent online?
My guess is it’s just “brain working faster than fingers” syndrome. You use your thumb to hit the space bar, and sometimes it gets out of synch with the rest of your fingers. I often screw upt he spacin gof words when I typef ast.
My guess is that hitting the space bar is sort of an “automatic” thing when you reach the end of a word, whereas placing a comma is less so. So the thumb may have automatically shoved in a space before the brain tells your finger to stick a comma in.
The 'Tangle Fingers" syndrome or uniform vs. proportional spacing! Take you pick.
data point:
I have seen this error in student writing with increasing frequency. 5-10% of my students (postsecondary trade school) do it as a matter of course; i.e. not as a once-off typo, but with each an every comma. Some will even insist it is correct.
As long as you remember to put TWO spaces after the period , everything will be fine.
Is this still being taught?
:eek: Oh please please please don’t start this!!!
You see, I am a technical writer. About every two-four months, someone will post to a tech writer mailing lists I read, with a variation on the theme of “What’s all this about one space after a period? Isn’t it two?” I must then suffer through an explanation, corrections to the explanation, etymology of the explanation, debates about the etymology of the explanation, etymology of other punctuation variations, and so forth and so on.
To quote Bill Cosby’s wife: “I HAVE HAD ENOUGH OF THIS!”
The next person who posts anything even remotely related to one space versus two after a period will get my personal, hand-crafted transcription of the Internet Light Bulb…
chiseled into five 9 foot by 11 foot by 2 foot granite slabs…
dropped on his or her head…
from a great height. You have been warned.
So , how ya doin? 
I couldn’t resist.
Since I know of no example in proper English where there is a space between the preceeding word and the following punctuation mark(s), the reason for this practice is:
IDIOTS!
I think that parenthesis (but not your specific example) are a good example of space between the punctuation mark and the preceding word.
Give an example, then.
Oh. You just did.
Then maybe I’d better change the def to “associated” word instead of preceeding word. A start paren symbol is not associated with the preceeding word, (all?) other puncs are.
Are you trying to be ironic here?
I’ve found that people educated in South Asia tend to display odd styles of spacing - namely, no spaces after periods or commas. This was just a couple of data points, so I don’t really generalize.
But what i’m trying to say is that it could be indicative of people schooled outside of non-English countries.
For what it’s worth, when I’m writing in a technical context and would have an equation or number at the end of a sentence or clause, I leave a space between the math and the punctuation. For instance:
Newton’s Second Law says that F=ma .
This is to avoid any confusion that might occur if someone thought the punctuation were part of the equation (which can carry meaning, sometimes). But I still put the apropriate spacing after the punctuation mark, as well, so I don’t think this is what you’re referring to.
Well – aside from dashes which usually get spaced on both sides, or hyphens which are un-spaced – I think there’s at least one other punction mark “associated” with the following word.
To tack on to this discussion, why has it all of a sudden seemed to become prevalent that people end their questions with a period? I see it happening more and more. 
I always want to ask why this is done, but refrain for fear of offending anyone. However, it’s driving me berserk!