Just like the question about your experience teaching adults, the interviewer may just be checking to be sure you know that there is a difference between the methodologies used and engagement level online than in traditional education. He or she is also looking for what your experience level is (“I have X years experience teaching in XYZ platforms teaching ABC subjects” is a nice way to start this one). If you have no experience teaching online, just be candid about it. “I have experience doing ABC, but I have yet to teach online. However. .I believe an online instructor needs to…” and this is where your teaching philosophy comes in. What does an online instructor need to do? What open source platforms have you used just to learn them online (Moodle etc)? Did you have experience as an online student that transfer into the classroom as a professor?