I did not know about that!

(Quick summary: n-gram analysis shows that women use more pronouns than men, among other distinctions.)

Ok, there does seem to be such a thing as a gender difference in writing style. Even within genres.

Two writing samples, one male and one female, from humanities journals: First:

Machiavelli's advocacy of force and fraud in the conduct of politics is the key teaching that has secured his reputation as "Machiavellian" and that has led to the conception of "The Prince" as the first document in the Western tradition to lay bare the dark, demonic underside of civic humanism. But this interpretation overlooks the degree to which a politics of intense competition and personal rivalry inhabits the humanist vision from antiquity, producing an ethics of expediency and a rhetoric of imposture that seeks to mask its alertness to advantage behind the guise of integrity and service. This vision is nowhere more apparent than in Cicero's "De Oratore," which exerted a powerful influence on the Italian humanists of the quattrocentro in whose direct descent Machiavelli stands. Deception, to put it simply, is an acknowledged and vital element in civic humanism long before "The Prince." The difference is that Cicero typically couches it in a sacrificial rhetoric that is euphemistically inflected while Machiavelli opts for a hard-edged rhetoric of administrative efficiency to make his case. But the stylistic differences, important as they are, should not mask the essential affinity between the Machiavellian doctrine of princely fraud and the Ciceronian ethics of gentlemanly dissimulation.

Second:

This article analyzes the intellectual content of civic humanism in the specific context of Medici power, asking the question: what ideological role did civic humanism play in Medicean Florence? It argues that there is no contradiction between the ideals of civic humanism and support for the Medici regime. On the contrary, civic humanism could be used to justify and legitimate Medici power. The article analyzes the writings of principal humanists such as Leonardo Bruni, Poggio Bracciolini, and Francesco Filelfo, showing that Hans Baron's republican "civic humanism" was compatible with different constitutional forms and different distributions of power.

Two excerpts from New York Times articles, one male and one female:

First:

Under newly fortified Republican control, many state governments started the year pledging forceful action to crack down on illegal immigration, saying they would fill a void left by the stalemate in Washington over the issue. Gov. Susana Martinez of New Mexico backed a repeal to a law granting driver’s licenses to illegal immigrants. Now, with some legislatures winding down their sessions, the lack of consensus that has immobilized Congress has shown up in the legislatures as well, and has slowed — but not stopped — the advance of bills to penalize illegal immigrants. No state has passed a law that replicates the one adopted last April in Arizona, which greatly expanded the powers of police officers to question the immigration status of people they stop. Still, immigrant advocates in many states say the debate has clearly shifted in favor of tougher enforcement. They say they have had to fight just to hold the line on immigration issues that they thought were long settled.

Second:

With the referendum over the constitutional amendments that will shape Egypt’s immediate political future just days away, the country’s nascent political forces were squaring off on Sunday, scrambling to influence a choice that leaves many confused. The Muslim Brotherhood and rump elements of the disbanded governing National Democratic Party, which both stand to gain the most from a rapid rebirth of electoral politics, support the amendments. Arrayed against them is much, but not all, of the remaining political spectrum, centered on the young organizers behind the Tahrir Square demonstrations who fear a yes vote would ultimately rob them of their revolution. Yet everyone agrees on two things. The referendum, which is scheduled for Saturday, will be a milestone and the first one not rigged outright in about 60 years. “Whether we accept the amendments or we reject them, either situation means a page in our history will turn,” said Amr Shubaki, a political analyst at the state-financed Ahram Center for Political and Strategic Studies.

Two excerpts from short stories, one male and one female.

First:

An old man with radiation scars surrounding the chromed half of his face limped down a salt-grass covered dune. Metal armatures creaked under his clothing as he thumped heavily across dry sand to wet, scuffing through the black and white line of the high-tide boundary, where the sharp glitter of cast-up teeth tangled in film-shiny ribbons of kelp. About his feet, small combers glittered in the light of a gibbous moon. Above, the sky was deepest indigo: the stars were breathtakingly bright. The old man, whose name was Aethelred, fetched up against a large piece of seawrack, perhaps the wooden keel of some long-ago ship, and made a little ceremony of seating himself. He relied heavily on his staff until his bad leg was settled, and then he sighed in relief and leaned back, stretching and spreading his robes out around him.

Second:

Kalak rounded a rocky stone ridge and stumbled to a stop before the body of a dying thunderclast. The enormous stone beast lay on its side, riblike protrusions from its chest broken and cracked. The monstrosity was vaguely skeletal in shape, with unnaturally long limbs that sprouted from granite shoulders. The eyes were deep red spots on the arrowhead face, as if created by a fire burning deep within the stone. They faded. Even after all these centuries, seeing a thunderclast up close made Kalak shiver. The beast’s hand was as long as a man was tall. He’d been killed by hands like those before, and it hadn’t been pleasant. Of course, dying rarely was.

Do you think Alicorn's style doesn't have the characteristics I described, or that such writing isn't statistically likely to come from men?

Well, she thinks explicitly and abstractly, like most people here, and I suppose that could be more common in men, but I don't think I've noticed anything especially male or female in her prose. I didn't notice an unusual lack or predominance of pronouns. (Actually I think Alicorn, more than most LessWrongers, tends to illustrate ideas with anecdotes about individual people, whether real or hypothetical. So that would mean more pronouns -- but then again, Eliezer has the same habit, and I don't know if that means you'd consider his writing feminine.)

This link is not stable. Google uses filter bubbles. I don't have the same first results as you do.

In fact, the first two results for me point to LessWrong directly, the third to an MLP fan wiki, and the fourth to a random news article that apparently misspelled "unicorn".

"alicorn gender site:lesswrong.com" with the date restriction of before Feb 24 2010 (when she posted a question about correcting her gender in someone's blog) gives me a pretty unambiguous second hit.