For the last four years, I've been certain that my students had never discovered this blog. The reason I was so certain was that I figured if the students had seen it, they wouldn't keep quiet about it (but, rather, would be quick to show off their sleuthing). Therefore, by the contrapositive, since I hadn't heard any students talking about the blog, I could be sure they hadn't found it. QED.
Then today, my last day teaching high school for the foreseeable future (last day of classes, that is; we still have exams and such), two students (graduating seniors) told me that they had been enjoying my blog. As in, they've been aware of it for some time (they may even be reading this post) and hadn't mentioned it until now. So I had underestimated their self-control, and/or forgotten that seniors aren't the same as freshmen.
There isn't actually anything incriminating here. As I've said from the beginning, there has always been a possibility that students would find this blog, and even though I don't use my real name on the blog, it's not particularly anonymous (there are plenty of places elsewhere on the Internet that connect my name to this blog). So I don't talk smack here about my students, colleagues, or supervisors, and I don't discuss anything personal that I would worry about falling into the wrong hands. So the biggest consequence of this discovery is that it means the students will find out that teachers have lives outside of school. But it's ok, since they're about to graduate anyway.
Lesson for teachers: Never underestimate your students.