A fine post from Chris Blattman lays out the rights and wrongs of student emails to professors.
I had a student at Western Ontario email from an email address along the lines of "email@example.com". Not a good idea.
The comments are interesting too. Like Chris, my personal rule is to have undergraduates call me "Prof. Smith" and graduate students call me "Jeff".
Who was my favorite student this term?
1 year ago