I participate in a couple forums where there can be heated political discussions, I fond that I tend to ignore the comments of people who can't spell or write properly, no matter which side of an issue they're on.
Typing is my downfall....
I'm sorry what? I was ignoring you.
as an earlier poster said, there are people who do not have a great grasp of the arbitrary rules of spelling and grammer, or even of vocabulary who are, none the less, very smart. If someone is communicating in a second language do you ignore them? I gotta say, beyond basic object/subject/verb brain structure level sentence structure I don't get that worked up about grammer. Spelling can be more of a problem as we have so many words in english that sound the same, have slightly different spellings and vastly different meanings. There, their and they're is a good example of that. Of course, if we are going to get all rules driven about language then we have to come up with a solution to the the problem of tear and tear.
'I felt a tear run down my cheek as I watched the tear run down my favorite coat'