When I view the profile of anybody that hasn't filled it's bio it says this:
Apparently, this user prefers to keep an air of mystery about them.
I think that it should say this instead:
Apparently, this user prefers to keep an air of mystery about it.
I've highlighted what I think that is a fail. However English is not my mother tongue.
I think that this may refer to the user and not to a bunch of users.