Tardis:Sentence spacing

Typography and punctuation Tables → Section headings → Use sentence case → Quotation marks → Italics → Capital letters → Bold text → Vertical spacing → Apostrophe → Comma → Period → Semi-colon → Movable type → Sentence spacing

You can put two horizontal spaces after a period, exclamation point or question mark if you want. But the bot will correct your typing to the 21st century standard of a single space.

Shortcut:

T:SENT SPACE

Although there has been some sporadic discussion about adopting a standard, the community has never actually ruled on the number of spaces which should follow a period or other full stop. Until a definitive ruling comes from forum discussion, editors are at liberty to use either one space after a period — which is the current standard on most online style sheets — or two, which was the prevailing rule in business until about the year 2000.

That said, a code cleaning bot does actually ensure that only one space exists between a full stop and the next character. However, this bot is not in continuous operation, which means that you will occasionally find instances of double-spacing around the wiki.

Still don't have an idea what this rule is about? Read more at wikipedia:sentence spacing.