Back in January, I posted about why I consider grammar to be important. Since then, I've learned that there's a term for me (well, a nicer one than the usual). I'm a grammar prescriptivist. That takes away the implication that I go around berating people about their grammar mistakes (I don't), while making me sound all smart and stuff.
There was a recent post on the Harvard Business Review, written by the CEO of iFixit. He won't hire people with poor grammar, and his reasoning is sound, to me. In today's employer's market, he could have any justification he wanted for refusing to hire the people he doesn't want working for him, within legally protected limits. But I can't find fault in his assumption that those who pay attention to grammar also pay attention to other small details. Detail-oriented people are the ones he wants working for him.
At work, I'm the detail person. I'm the one who proofreads emails and cover letters, looks over monthly billing for errors (which I used to do more formally), is in charge of the most exacting paperwork, and who people snag for some picky little error in one of the computer programs we have to use.
Outside of work, my detail orientation isn't appreciated. My family and friends throw up their hands in exasperation if I correct them, and I read regular screeds online about how "GRAMUR DUSNT MATER."
I do recognize the value of descriptivism (basically, the notion that it doesn't matter, so long as the intent was communicated). I also think attention to grammar and spelling show a level of respect I prefer in those I wish to communicate with. I don't expect my friends to speak in full, grammatically correct sentences, but I do expect their posts to contain the right version of "its" in enough of their posts that I know they know the difference (and they can blame autocorrect for the rest). If I think they don't, I'll try to gently point it out.
With writing, all you have is your words. You don't know my expression right now, or in what tone I'd speak this post, or how much sleep I got last night. (Not a lot; thanks for asking.) The words are devoid of context. They're your only link to the person reading those words.
And call it snobbish, call it elitist, call me full of myself, but bad spelling and consistently poor grammar say a lot about your education and intelligence. If a person can see at a glance that you lack the ability to learn a set of rules and follow it, why should they trust anything you have to say?
The importance of grammar applies whether you're typing comments on a blog post or submitting to an agent's slush pile. If you honestly don't care how others perceive you, then you can feel free to ignore any and all rules. But, if you want to come across as well-educated or publishable, I recommend you read up on the rules.