There's an interview with Londoner paramedic and blogger Tom Reynolds in today's Guardian. He's got a loyal audience that appreciates his writings, but Reynolds doubts that he comes across as a good writer. "...I look at [my posts] and think, oh god I've used too many commas ... the only thing is I write fairly plainly. I think that's the main thing." he says.
I agree completely on the grammar issue: It's the story or the message that's important, not the linguistics. One's knowledge of where to put the commas is a matter of secondary importance when blogs are concerned. But this is where my agreement ends, I think Reynolds writes fascinating entries. Check out the superb blog here.