In a way. I mean, on the internet, a few typographical errors, fair enough. But if you've been on the internet for any time whatsoever, someeone will probably have pointed out that your spelling is absolutely atrocious, you'll likely have got some kind of spell-checker.
As long as there's some sort of logic to it and it's not the work of more than 20 seconds to figure out what you're trying to say, you'll generally be fine.
I'm also concious of grammatical errors, though that's often balanced out by me thinking "Oh well, maybe English isn't their first language, and they're basing the spelling they're using off the one they've heard. Fair enough."
Consistent misspelling or deliberately obtuse use of capitalisation, though, do tend to grate after a while.