Hi SG, I meant to make a comment on this before but somehow forgot. I am so glad you and Gigi brought this up.
I'm in technical communications. One of the biggest points I ever learned was that writing on the internet doesn't convey a lot of information that we usually convey in person: a lot of information about the sender and his/attitude is brought across through body language, eye contact, tone of voice, and other physical means we don't see online.
And...readers often project themselves into that writing. Meaning, if I say something, a reader can immediately take it the "wrong" way. I can for example tell someone to "bite me" and mean it jokingly. But another person who doesn't know me well can take that as an insult.
However, language patterns do reveal a person over time. Often times I read a person's posts for a bit before responding to them. Never underestimate a person's ability to analyze your language patterns. You can come across as an arrogant PITA without realizing it or you can come across as a total fool, etc. Even our user names here "convey a message." Yours conveys an idea of someone who knows how to get through life and has a positive self-image. I remember years ago there was a poster for a short time with a user name of TheMan. First thing that came to mind for me: what a jerk! But it's also easy to spot when someone is stuck or hurting...there is a lack of positive action (verbs) in what they write; it's easy to spot someone who needs a little empathy...there are words that say "I feel down" or "I feel something." We don't always do this consciously when we write, it's just as if we were speaking.
Too another idea to remember is that comprehension/understanding between two people communicating is never 100%. You may tell me a message and I have to filter that through my background and experiences and how I am right now (if I'm sick or tired or jazzed up on too much coffee lol). I will not process 100% of what you're telling me accurately so there is by nature a lot of repetition and reinforcement going on between us until we're in agreement.