I suspect it depends on the individual, and the particular online course.
Some years ago I took the Open University Photography unit - which is done entirely online.It did include a full web forum system for students to discuss hte course and share images, and all assignments went to a specific tutor who personally marked and commented on them.
I did learn a fair bit, but part of that was that an online photography course should NOT have limits / restrictions on photo uploads (after getting a negative comment on one of my shots that was due to having to reduce quality to get within the limits!).
I've also been on a number of workshops, and read a number of books - and tend to take the view that there is no 'magic bullet' to learning photography.
What you need is to take photographs, and to have some form of input to try different things and find out what works best (photgraphically) for you (and in different circumstances) - what works best for you (learning wise) may well different to me.
