This is a very good post. I've been very cautious as to how I address people here on JU, specifically for this reason. I try not to guess until I've read a few articles/comments and even then, if it's not obvious, I stay gender neutral.
mig, I never mistook you for a man, but at first I did mistake you for possibly Korean. nuna, in Korean, means older sister (to a guy).
Slightly related note - a female Korean teacher in my schoolhouse recently expressed to me her disgust in our textbooks. In almost every case, our textbooks will address male characters (in dialogs) as 'teacher', 'doctor', or some similar term, while women are almost always referred to as 'miss'. Also, in the unit where the students learn vocab about jobs, the professional jobs (teacher, civil servant, doctor, even soldier) are all identified with men. The jobs that are left to the women? Secretary, store clerk, nurse, and housewife! What makes this even more poignant is that most of these textbooks were written and edited by women! I was actually ashamed (a little) that I hadn't noticed this until she pointed it out.
