Most times, I find Escapist users let things like a couple of spelling/grammatical/punctuation mistakes slide. It's only when the user's whole post is piss-poor, in terms of the aforementioned, that it gets called on for its lack of legibility. Funny enough, I was about to end the sentence on 'on', but remembered that someone got called on it, heh.
I myself tend to ignore posts where the person speaks like the average internet user, simply because it gives me a headache. I find posts without any form of capitalisation, punctuation or grammar not worth my time, and frankly, it's a bloody pain. If I, a terrible speller, on top of one who's barely passing English, can take the time to proof-read my work, write in somewhat comprehensible English and generally put some care into my posts, then so can you.
Oh, and for those complaining about the dictionaries spelling the incorrect American way, there's an alternative. here's [https://addons.mozilla.org/en-US/firefox/addon/3099] a British one. Not so hard looking for these two, and I've been using the Australian one since I've joined (which is why my spelling doesn't seem to bad).