Once when I was bored I started searching through LiveJournal to see if there were any public diaries by people working for the same chain of English schools as me. Sure enough there were…and one of them contained stuff I don’t think the teacher should have made openly available. Nothing too shocking really, mostly a lot of bitching about coworkers (using their real first names), but also insults of students and quite a bit about being hot for a student who was sadly too young! I didn’t read enough to be able to tell if the student was actually underage, but either way that’s the sort of thing you wouldn’t want your boss stumbling across.
As the teacher gave the name of the chain of schools, the general region of the school, and the first names of coworkers, I think I could figure out exactly which branch it is and the teacher’s identity using the school directory at the main company website. So could anyone else. If I were teaching in the same region I probably would have been able to figure out the particular school just from the first names, as I would have run into the same people at area meetings.
If you’re going to talk about students, patients, or even coworkers at any kind of job in an open forum, I think it’s best to avoid using any real names at all. Not just names of people, but the name of your place of work too. To be safe, it’s also a good idea to change unimportant details like DoctorJ mentioned, and avoid including too many details that aren’t crucial to the story. For instance, I’ve referred to one of my coworkers as “The OBG” (“Office Bad Girl”), or students as “karaoke-loving office lady” and “teenaged boy who likes Tolkien”. These are pretty generic descriptions, but they’re enough to set the stage. It might be more colorful to refer to some of The OBG’s exploits, but for the sake of any story I’d wish to tell about her it’s enough to know that she is The OBG. You don’t really need to hear about her glass eye, her yakuza boyfriend, or that she put herself through school working as a stripper in Yokohama.