Teaching just from the Web

I wonder if it will ever be good the do all teaching at all grades from the web. Is there a grade that you just can't because you have to be face to face and then is there a grade where you can do partial and at what age is it okay to go all online learning. I know that in highschool they have online classes but do the students get as much out of those as they would if they were face to face. My sister-in-law did "fit for life" online but if she did not exercise like she was suppose to she just lied and said she did. Is there a way to get past this of is it more based on trust. Well right now i just don;t know.