"According to Rosemary Feal, executive director of the MLA, [the American style] was instituted in the early days of the Republic in order 'to improve the appearance of the text. A comma or period that follows a closing quotation mark appears to hang off by itself and creates a gap in the line (since the space over the mark combines with the following word space).'"
Ironically, though, this article only uses the "logical punctuation" style once - in the title.
On the face of it, punctuation is not the most electrifying of subjects. A comma is a comma, a period is a period, and a semicolon is an argument waiting to happen. Look past squabbles over grammar, however, and punctuation's staid veneer peels back to reveal a seething, Darwinian struggle that has played out over two millennia of the written word.