There's quite a difference between those using "net shorthand" and those who literally cannot spell.
The former, I usually have no issue with, for as long as I get the gist of what they're trying to convey, I am fine.
Those who obviously could not spell their way out of a two letter word spelling contest? Well...I guess it bothers me a bit, more out of an odd, misplaced, genuine concern as to WHY they cannot spell, or differentiate grammar, etc...but most of the time it doesn't make me feel their point doesn't merit consideration.
It's an internet chat board, not an online college (and don't get me started on some of the things that relatives who teach in college show me that their students have actually passed in as work, holy cow. )