Alicorn:

Additionally, people who identify me as male (or choose to express their uncertainty with male pronouns) on the Internet aren't typically doing so because there's positive evidence to that effect...

Have you considered that your writing style might be unusual for a woman? Even based on a small sample of writing that has no obvious clues, it's usually possible to guess the author's sex much better than chance. You write in a very technical matter-of-fact style, with long, complex, and yet very precisely constructed sentences, and take unusual care to avoid ambiguities and unstated implications. (You'd probably be a great textbook writer.) Whatever the reason for this state of affairs might be, people who write like that are overwhelmingly men.

Also, why not simply use a female name if you're bothered by this?

I know what I said about unicorns above, and I think that's still relevant, but I disagree with your characterization of the gender misidentification as "stereotyping".

Given that there are more men than women on Internet discussion sites, and especially on Less Wrong, wouldn't it be reasonable to guess that any given poster is male, unless there's evidence to the contrary ? By analogy, if I knew that a bag contained 75 black marbles and 25 white marbles, why shouldn't I guess that a random marble, that I pulled out of the bag without looking, is black ?

they're guessing based on my location ("the Internet" or the specific site), which amounts to careless, casual stereotyping and rankles horribly

My prior probability that someone is male is about 50%, knowing that they read Less Wrong amounts to about +10 dB of evidence that they are male (as of the last survey), so the posterior probability that someone is male given that they read Less Wrong is about 90%. How does Bayesian updating amount to careless, casual stereotyping?

I completely agree. Well, it doesn't rankle for me in the same way because I probably post a lot less on the Internet than you do, and thus get a lot fewer assumptions. (Also, I kind of like the thought of people not knowing my gender.) But I completely agree that the Internet, and especially sites like LessWrong, is assumed to be populated by males.

My priors before I started paying attention at all (i.e. before the first time it came up in a conversation I was part of, on the internet, that someone was uncomfortable / sad / whatever that they were being referred to as the wrong gender - which, for record, was a post-op man genetically female who still had a few culturally-programmed female-expected behaviors) were around about .4 female to .6 male for any random person I meet and discuss with on the Internet.

Even that .4 seems rather high compared to the base stats I've seen since then for some populations, but there's apparently some factor which makes me more likely to engage and enjoy discussions and interactions over the web with women, for some reason I don't yet understand.

However, since then, I've had to update downwards. Even with my abnormal encounter rates (e.g. meeting 30% women in communities that are 3% women overall), on average I still only expect and observe that I "befriend" (or otherwise engage and interact with more actively with) women only one in five times of such people, i.e. the other four are men. This if I only include so-called "normal" men and women, because I also end up meeting abnormally high numbers of transgenders, asexuals, queers, and other nonstandard genders.

On top of that, out of the women that I do tend to interact with (which are already at less than 0.2 expected rate), only one in two cases I'll end up having to refer to them before their gender becomes "revealed" in some manner (sometimes because of an obvious nickname). Of the half where I do, nowadays I use gender-neutral format, but before I started doing so, only one in four (well, three out of thirteen to the best of my memory, in total) got slighted/offended/whatever that I used male pronouns.

Which basically ends up with there being an approximately 2% expected probability that for any person I start interacting with I might use a male pronoun for a woman that will be affected by it, unless there is a high amount of women who get hurt from wrong pronoun usage but never reveal this. This is including my current rate of female:male encounter ratio, which I've already confirmed is abnormal from other stats (e.g. I've eliminated cases like women just befriending more people than men or similar situations).

I would expect that most people have their expectations somewhere around this or even rarer, so I can't fault them for using male pronouns on the Internet by default without first having to fault them for thousands of other, much worse things.

For bias evaluation purposes: I have been identified and referred to with female pronouns at least twice on the Internet, and wasn't offended (in one case, I was actually flattered, for various contextual reasons). In the past week, excluding work colleagues and LessWrong, I've maintained more meaningful Internet-based interactions with three regular men, two women, and one genetically-male unclear-someone who hasn't quite yet resolved his own personal gender-identity yet and would probably fall in some gray area between "queer" and "pre-op transgender".

You sometimes (how often?) get ignored because you've been mistaken for being female.

He gets ignored for being mistaken for not being Joshua Zelinsky.

I've read that essay, it's largely responsible for my current views (or at least made me much more vocal about them). The only issue I have with it is that it's almost too subtle. I didn't really get what was going on until I skipped down to the end. I sent it to a feminist friend of mine and she got annoyed with it and stopped reading before she understood what the point was.

I remember reading that article, and not being impressed. He lumps all the sexist talking points into one essay, and therefore it ends up looking like one big strawperson. He may have good points, but unfortunately his own essay undermines them.

So we should not stereotype people's geneder based on the fact that they post on geeky websites (stereotypically male) but we should stereotype people based on their association with unicorns (stereotypically female, supposedly)?

(And why are unicorns supposed to be stereotypically girly? Horses are typically a symbol of strength and masculinity. So an horse with a large horn on its forehead, well...)

I wasn't really sure how to word that sentence to strike the right emotional note (I've changed it a little, hopefully for the better).

I think it's legitimate to argue "you should not make assumptions about gender until you have some actual evidence to go on. " I don't think it's legitimate to argue "my name relates to unicorns therefore you should assume I'm a girl." Either people associate the word alicorn with femininity or they don't. And since this issue has come up multiple times, apparently enough people don't make that association that it's an issue.

I also don't think the world would be a better place if more people DID think Alicorn was a girly name. My favorite game is Robot Unicorn Attack. I've considered buying Invisible Pink Unicorn Merchandise. I don't feel a need to associate my identity with it, but I think it'd be a better world if preference for unicorns didn't signal gender or sexuality at all.