The HTML rendering engine in your browser actually consolidates each block of white space into a single visible space character. If you view source, there are two spaces there. So, there's a good reason not to use two spaces, as the web will only show the one.

That's actually an argument for why it doesn't matter, so we can all continue to do as we please.

Is there a good reason the browser messes up my spacing? Certainly not for readability!

It's because spacing is used for both structure and presentation in HTML, so something like:

    <span>This is some text</span>
    <span>while this is some more text.</span>

shouldn't render the 4 indentation spaces that I used.. If it did we'd have to pack it all into one line. Can be adjusted appropriately with CSS though, if people here were obsessive about the presentation of their spacing.

That's not a good reason to use two spaces -- that's a good reason for people who think one space is "the standard" to stop haranguing people who use more than one character width to separate sentences when typing.

There's something kooky going on with that page. I think the CMS used for that site must be substituting one type of space character with another in Unicode, or something like that, so that the browser does not "know" how to collapse the two whitespace characters into a single whitespace character.

When I copy the two whitespace characters between sentences there into separate text files that contain nothing but those whitespace characters, then `diff a.txt b.txt`, the result is that they differ, so there is definitely some difference between the two types of whitespace characters used between sentences.

I've written a text formatting tool designed to preserve multiple whitespace instances on the Web. It used ` ` for the first of every pair of standard single space characters. Apparently, this CMS is doing something similar, but even tricker because it doesn't show up in the source as an HTML entity, and perhaps less well thought-out because for some reason the nonbreaking version space character used is the second of the two (which results in weird ghost-spaces at the beginnings of lines sometimes, as you discovered).

Indeed, performing a hex dump, the second space seems to have been replaced with 0xc2 0xa0, which is UTF-8 for:

U+00A0 NO-BREAK SPACE character

Which is the same as HTML entity  

Thanks for taking it a step further. I was to lazy to go that extra mile.

Well . . . several keystrokes, anyway, plus a Google lookup.

Actually, its your browser that renders multiple spaces as a single space. If you want multiple spaces in your HTML you have to use the non-breakable space tag " ".

I believe there is      unbreakable space character you could use for that purpose.