Sure, a blog is close to email or instant messaging in terms of ease and informality. But it’s also close to traditional publishing in its permanence, though lacking the quality control brought by the editing process.
So does spelling matter? I regret to inform you… No, I’ll leave it to a PR practitioner who recruits graduates to spell out the plain truth.
I hope you know who this is aimed at. I won’t embarrass you by linking.
PR Studies 
Too true. I am acutely aware that the quality of writing on my blog frequently falls far below that I would allow for traditional copywriting channels. We insist that news releases, articles and even letters are proofed by a second person, but don’t apply the same quality control checks to our blog entries. At least Ian Green at Green PR makes as many mistakes as me and he’s an ex-editor 😉
I wonder how many of your readers thought, oh no, does he mean me?!?
Seriously, I always show first year PR students a slide based on a paper by your Leeds colleagues Ralph Tench and Jo Fawkes, Mind the Gap:Exploring different attitudes to PR education between academics and employers.
Asked what skills they valued 98pc of employers rated literacy as very important.
Some of my students debate whether they should study journalism; yes, I say, if only to polish their spelling and grammar.