For at least two centuries, it has been standard practice in the United States to place commas and periods inside of quotation marks. This rule still holds for professionally edited prose: what you'll find in Slate, the New York Times, the Washington Post— almost any place adhering to Modern Language Association (MLA) or AP guidelines. But in copy-editor-free zones—the Web and emails, student papers, business memos—with increasing frequency, commas and periods find themselves on the outside of quotation marks, looking in. A punctuation paradigm is shifting.
Indeed, unless you associate exclusively with editors and prescriptivists, you can find copious examples of the "outside" technique—which readers of Virginia Woolf and The Guardian will recognize as the British style—no further away than your Twitter or Facebook feed. I certainly can. Conan O'Brien, for example, recently posted:
Conan's staffers' kids say the darndest things. Unfortunately, in this case "darndest" means "incriminating".
The British style also rules on message boards and bulletin boards. I scanned four random posts in Metafilter.com (about Sony Playstation's hacking problems, the death of Phoebe Snow, the French police, and cool dads) and counted nine comments with periods and commas outside, seven inside.
I spotlight the Web not because it brings out any special proclivities but because it displays in a clear light the way we write now. The punctuation-outside trend jibes with my experience in the classroom, where, for the past several years, my students have found it irresistible, even after innumerable sardonic remarks from me that we are in Delaware, not Liverpool. As a result, I have recently instituted a one-point penalty on every assignment for infractions. The current semester is nearing its end, but I am still taking points away.
Why has this convention become so popular? I offer two reasons, one small and one big. The small one is a byproduct of working with computers, and writing computer code. In these endeavors, one is often instructed to "input" a string of characters, and sometimes (in the printed instructions) the characters are enclosed in quotation marks. Sticking a period or comma in front of the closing quotation marks could clearly have bad consequences. So, for example, the Chicago Manual of Style (16th edition), which otherwise endorses the American way— "This is a traditional style, in use well before the first edition of this manual (1906)"—makes an exception in the case of computer instruction, illustrated by:
name your file "appendix A, v. 10".
But the main reason is that the British way simply makes more sense. Indeed, since at least the 1960s a common designation for that style has been "logical punctuation." The best way to grasp this is to look at an example, such as what Slate commenter Dean Hamer wrote under a recent article about PBS and NPR:
[I]ronically, given the anecdote about "Tales of the City", PBS is the ONLY widely available channel that has any serious LGBT content; e.g. documentaries such as "Ask Not" and "Out in the Silence".
"Tales of the City" and "Out in the Silence" are units—consisting of the words and the quotation marks. Insinuating a period or comma within the unit alters it in a rather underhanded manner. American style is inconsistent, moreover, because when it comes to other punctuation marks—semicolons, colons, exclamation points, question marks, dashes—we follow British/logical protocol. Dean Hamer would pass muster in any U.S. newspaper or magazine, for example, if he were to write: I am a big fan of "Tales of the City"; did anyone else see "Ask Not"?
If it seems hard or even impossible to defend the American way on the merits, that's probably because it emerged from aesthetic, not logical, considerations. According to Rosemary Feal, executive director of the MLA, it 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)." I don't doubt Feal, but the appearance argument doesn't carry much heft today; more to the point is that we are simply accustomed to the style.