It seems like everyone these days is using she. Its perfectly acceptable english to use 'they'. For example: Once a user is signed in, they are taken... Much better imo, as the gender is meaningless in that sentence.

Absolutely. People complain about it being plural, but words in English have both number and gender, and I don't see why being "wrong" on the number is any worse than being "wrong" on gender.

That said, it's not "wrong" at all because English has a long history of using the word "they" for a generic pronoun. It's basically a different word from the "they" in "they are my friends", just written and pronounced the same.

Really? I see she used all the time. It doesn't necessarily valorize anything; it's just like using he for a hypothetical user.

Years ago, I read an article (probably on HN) that advocated using "she" as a pronoun. The article itself was slightly sexist, reasoning that women will complain about gender equality when writers use "he" to refer to the reader, but men won't complain when "she" is used, but it was good advice.

Can't find any reference online, but remember that some US grammar teacher had proposed using him'er and his'er but just never caught on.