Yale Law Student Will Baud puts the cat among the pigeons: should (can) professors limit what students say about them in blogs? FWIW, my view is that class is bloggable, but that it's bad taste to blog any private conversation, whether with a professor or anyone else, without that person's consent. Smart students will, however, consider that people, yes even professors, may figure out who they are, and modulate their remarks as they would in any other signed communication. Plus, once you post something, it's pretty much up there for ever.
I certainly feel very constrained, maybe the word is “shy”, about posting much personal stuff here. Pretty much anything that mentions my family I clear with my spouse.