Many people who watch my YouTube videos leave comments. Sometimes the comments thank me for posting the video, tell me that viewer has learned a lot, and that some like my style (while others don't!). However, I also get a lot of questions seeking further help - and I find that it is time consuming to answer them all. I take the view that if a student had asked the same question face-to-face, I would respond with "Did you attend the class?", "Did you study the course notes?", and "Did you read the recommended text book?". So I ask myself should I respond to all video comments when I feel it is clearly a student's responsibility to do their homework first?
In general, I do not respond to comments unless I can do so quickly and easily. As I write, my channel has 11,615 comments, so I feel with this volume that I cannot respond to them all. I'm guessing that responding to comments improves my rating in YouTube's algorithms, but I basically do not have the time to do so.
One of my most popular videos (a surprise "hit" for me with 867,638 views since published January 11th, 2012) is How To... Calculate Mean and Standard Deviation in Excel 2010. This video has 261 comments and today I received a comment from a viewer looking for further help. The viewer should be able to check out other resources before they come to me - I am not an on-line tutor providing an education service. Nevertheless, in this case I will respond as I have used the viewer's post as an example here.