I am a spelling and grammar fiend.
I don't take it as far as some folks; one typo/misspelling/lack of punctuation isn't enough to send me to the comments section/reply button in order to completely ignore the content while I bash someone to death with Strunk & White. I don't assume a lack of proper grammar means that someone has nothing useful to say. Some people just never get punctuation, some people have dysgraphia/dyslexia/what-have-you, some people were busy doing much more interesting things in 8th grade while the rest of us were in class learning to parse sentences.
It does make it harder for me to read stuff when it's not "right", and my brain will refuse to go on until I have let it correct every "mistake" it sees. I am OCD about very few things, but this is one of them.
I've been reading another blog, Ex Libris Hieronyma, which I really like. Her misspelling of "alter" for "altar" was driving me a little nuts, until I considered the following possibility: if we witch-types do magic at our altars, thus altering things, maybe "alter" isn't the mistake I thought it was. At the moment, I have an altar at which I'm not doing any work; I'm just sitting at it and talking to my various gods. I have an altar in the temple/study where most of the work seems to be going on these days; maybe that's my "alter".
Too cutesy? Too much of that "language means what we make it mean" thing, when I think that most of us know that the words matter? Eh. Maybe you're right. But I had a new thought and got a new perspective, and I can't think of that as anything other than a good thing.