I'm the complete opposite to Alicorn, so I though I'd just pop in and say. I don't just keep track of gender, but also any other characteristics like age, occupation, nationality; personality etc. While I find it ok to just type like this on the internet, I find it much easier to actually communicate with people. Knowing these sorts of details help me interpret tone, which I think is a vital part of conversations, and the lack of respect for which often a source of internet conflict. I respond differently to aggression, for example, from high-testosterone males to females.

Having more accurate priors of the person I'm talking to also lets me decide if an argument is a lost cause, helps me choose between ambiguous interpretations, and assists me in making the most palatable presentation of my point.