Adherence to arbitrary grammar rules is a signal. It shows that the writer has training in what the rules are, and the ability to follow them. To some readers, this can be a signal of credibility. I don't care if the rules make sense; I care if someone will think less of my writing if I break the rules.
People often reply something along these lines. I don't entirely disagree, but I have some big reservations. First, which rules? That is, does it still bother you if a writer uses 'will' where some very stuffy people would prefer (even insist on!) 'shall'? If not, why not? If so, why? Notice that no matter which way you jump on this, you're already making choices. What about 'nauseous' and 'nauseated'? Do you insist on that distinction in writing? How about in speech? Do you correct people who say 'can' instead of 'may'? How about 'less' and 'few'? Do you say 'your being here makes me happy' or 'you being here makes me happy'? There's always going to be room for some pedantic asshat to correct you. It's up to you, however, to pick the cases where you push back, or shrug, or accept the correction quietly (because you've had the fight too often). You also have to decide who you want to impress. If you carefully rearrange all sentences so that they don't end with a preposition, you may impress the grammar school teachers and the self-satisfied pedants of the world, but you will only look silly to the professors of Linguistics over at Language Log[1].
So it's not entirely good enough to say "Just follow the arbitrary rules in order to demonstrate that you are a thoughtful, well-educated, intelligent person." It's always a case of pick your rules and your battles.
I do have to choose among rules. The choices that I make are also a signal. I am an American, and I work in a profession where writing is important. I try to make style and grammar choices that match those of well-thought-of American writers in my profession. I do try to avoid choices that might make some people think I don't know the "correct" definitions of words (nauseous vs. nauseated, for example). I don't care as much about "will" and "shall," because American writers I respect mostly use "will," unless they are writing statutes or contracts. Also, I try never to correct other people; I am not much of a prescriptivist.
This is similar to "geeks do not respect suits". Suits are meant to signal credibility. But since geeks value ability much higher than style, the suit, being worn by "less intelligent" salespeople and managers, became a negative signal.
Similarly, perhaps online the use of American punctuation is becoming a negative signal, showing pedantic training as a "professional writer" rather than a true ability to convey ideas.
It can also be a powerful signal of an unoriginal thinker, forever destined to do what they're told and to simply be a replaceable cog in a machine.
If you are looking for a technical writer, accountant, copy machine operator, security manager, etc. a rule follower is okay. These people don't ask questions, don't go against the grain and can be relied upon to simply produce output in a well structured process at a uniform consistency. In effect they are trained to produce fast food. This can be highly desirable in many cases -- but it shouldn't be lauded.
If you are looking for a novel thinker, a rule follower is the last place you want to go. You'd want them to know the rules, and be familiar with them, but not be chained to them/use them as a crutch or excuse. However, like most creative endeavors, if can be hard to get consistent, regular output. They aren't unaware of the rules, they simply ignore them. They aren't better than a person that can assemble words into sentences with the regularity of a automated assembly line, but they are definitely different.
Where it gets confusing is knowing the difference between somebody who purposely ignores the rules to achieve a desired output vs. somebody who is completely ignorant of the rules. I've personally found that people who are strict rule followers have the hardest time with this distinction.
When I am reading, I first look for signs that the author has been trained to know the rules. Later, I look for him or her to break them.
There's something about knowing that you are breaking a rule that makes it feel more legitimate to me. You are using your license instead of your ignorance. I enjoy seeing that in what I am reading.
Edit: I wrote this in part to encourage you to relax your style and care a little less. Tell me what you think :)
I recently finished Bill Simmons The Book of Basketball. He frequently breaks a grammatical rule, then includes a footnote saying something like "Yes, that really did deserve a double negative."
Understood, but what about this: Before reading this article I didn't know about these rules. In Germany, we seem to follow the "british way". Couldn't resist..
So this argument seems only to hold if you a) assume that your readers are from the USA (or NA in general, no idea about Canada?) so that they value this style and b) that they don't just stumble upon your texts: They need to know where you're from.
This is necessary because it seems that a British person could easily claim that you're incompetent because you follow the exact rule we're talking about, but it doesn't apply locally for him. Okay, that's a bad example. AE and BE in writing is probably different enough so that someone speaking/writing BE will just chalk this up as another difference.
But here comes the rest of the world. We know about fall/autumn, colo[u]r and whatnot, but I'd say that it's not generally easy to say where some english text originates from, geographically/where the author lives. So if I cannot distinguish AE and BE with certainty, do I blame you or a BE person for handling this "wrong"?
Knowledgable readers who care will likely know both standards; at that point it's a matter of consistency (or, at the very least, never do something that breaks both sets of rules).
I'd say that in this case I'd give more credibility to someone who follows logical punctuation, as long as they followed it consistently. I prefer it both logically and aesthetically, and, perhaps because of this bias, would wonder if someone following the "periods and commas inside the quotes" rule is just mindlessly following a rule.
Language evolves over time, and in my opinion logical punctuation has become common enough to be a credible choice. Most people these days take the "do not end sentences with a preposition" rule with a grain of salt, and I think that the MLA method of quoting is headed in a similar direction.
