I think it’s pretty clear what a teaching persona is, and we have likely all described our teachers with adjectives that reflect their personas – she’s funny, he’s a drill sergeant, she’s tough but fair, etc. In a physical classroom, instructors can read the temperature of the students (if they’re doing their job) and adjust their delivery appropriately. If their jokes are getting blank stares or people are offended by a well-intentioned joke, it can be relatively easy for instructors to make tweak the elements of the personas they display to students for various reasons.
However, I think for online instructors, it’s much more difficult for their persona to come across over email, through forum responses, and in brief live sessions or office hours. The online environment lacks that instant feedback you get from the students, and the majority of communication is written, which is fraught with opportunity for misunderstanding and miscommunication. In online communication, sometimes it’s difficult for humour to come across – I’m sure many of us have participated in a “flame war” that originated from a “joke” that didn’t sound like a joke.
So I think for online learning environments, you have to be even more careful of what you say because you’re lacking the element of tone/inflection. But because we recognize the deficits in written text, we can actually see how our online communication is evolving and changing to try to make up for that, using hashtags or “tone tags” (I don’t know what these are really called – I’m just making that up) like /sarcasm
It’s a constant challenge, but more and more tools are evolving everyday to overcome this barrier, so instructors can be more true to their personas without fear of those misunderstandings happening.