idiggory, King of Bards wrote:
Originally, it was done because typewriters required that second space (I believe to help with legibility, since each letter takes up the same space on a typewriter). Computers, however, space letters according to their needs, so a single space is generally enough.
It also has to do with the fact that most writing styles are pioneered by printers, and shaving that extra space saves them paper and (in the context of newspapers) space.
Later printers, yes. The origin of the double space actually goes back to the original old block style printing presses. Different blocks were used for different sized spaces, with the largest block used to separate sentences. The reasoning was because letter blocks were the same regardless of what was around them, which creates gaps in a sentence depending on which letters are adjacent to each other. A larger space was necessary to signify the end of a sentence. Since the letter before that space was small (a "."), it created a
large and unmistakable space.
Early typewriters were not only fixed in terms of the letters themselves but also monoscale (each letter took the same width on the page). The normal gaps between letters were even more variable and noticeable than on block printers. Thus, the convention of double spacing began to emulate the effect of using the largest block space between sentences that most people were used to seeing.
Unless you're typing with a fixed letter monospaced font, there's no reason to double space after a period for legibility. Some people do it just because that's what they were taught, but it's completely unnecessary 99% of the time. And as a couple people have pointed out, html automatically strips out the extra spaces anyway, so even if you do type them on this forum, they wont show up.
On the topic of strange writing habits though, I've got a dozy. Not sure where this friend of mine developed the habit, but he would do what he called a "soft return" when typing. Instead of letting the document software he was using manage word wrap, when he felt he was too close to the end of a line to fit the next word, he would hit the space bar until the cursor wrapped to the start of the next line, then continue typing. Of course, this inserted arbitrary numbers of spaces in his document, which looked fine if you were using the same software he used in the same font, with the same size. Of course, when I needed to take several dozen documents he'd written (on his Mac), and edit them on my PC, and print them out. Yeah. That was... "fun".