It was very interesting to observe that s/he had also a Custom Title: "Yes, really". The Custom Title
raised questions about this user being created by an admin or not, but nobody found out for sure how that Custom Title appeared.
I was pleasantly surprised that the three millionth user turned out not to be a spambot, so I assigned them the title. I don't know who they are, and they wouldn't have even known that I was the one to do it.