I'm a wee bit intolerant of bad grammar. I detest imprecision and am endlessly annoyed by sub-optimal punctuation. (I know some of it is writer's choice, but most often there IS a simple right and wrong.) In spending the last few days combing through blogs I've found some great ones, but I've also followed links to blogs where the writers had something less than an acceptable acquaintance with proper English.
Maybe I've been sheltered, but I always assumed writers made it a point to be, well, good writers. And I'm not talking about newbies who are just starting out, I'm talking about people who have published books and made a few sales. Often they're wondering why they're not doing better They have nice covers, maybe a nifty plot, but then I read the posts on the blog and I stop cold. Their grammar and punctuation is atrocious. And I don't mean just a misplaced comma here or there, but really nonsensical sentences that seem to have been typed out by monkeys and then randomly punctuated by drunken monkeys. Maybe drunken monkeys that had been dropped on their little heads. Really, the rules for semi-colons are NOT THAT HARD.
Suffice it say, I'm not going to pick up their books. Hopefully the books were edited by someone else, but I have a writing sample in front of me, and it's yelling at me not to waste my time.
So for dog's sake, read Strunk and White's Elements of Style. It's small. Then pick up Eats, Shoots & Leaves. It's fun. But trust me, if part of your self-promotion is blogging, make sure you're writing isn't chasing away your readers before they even open your cover.
(FULL DISCLAIMER: I am queen of the typos, because my mind has often skipped on to the next thing before I've finished typing, and sometimes when I read back over a post, I'll stop and wonder how that stray comma got there, but I do go back and change it. This is also why I always have someone else proofread my professional work).