That may be but I personally find it extremely difficult to juggle my everyday working life with an online class. I would much rather download and watch a video lecture on the way to work.

You can totally do that. The courses are 'synchronous' in calendar spans of time, not in lectures being broadcast live.

I think the synchronous model makes it easier to have small communities of students working through the same thing at the same time, helping each other.

On top of that it makes work of TA easier. Everyone works more or less on the same problem, be it programming assignment, quiz, etc. If there's a new question TA most probably remember what was in the last lectures and what are the common issues students are having this week.

Same for me.

I also find the assignments/exercises on the courses are first class and that's where a lot of the learning comes in especially when backed up by discussion forum activity from other students. Watching the videos on their own doesn't really appeal to me.

Just thought I'd add a data point in the opposite direction. I've signed up to two Coursera courses and two Udacity ones, and it's the Udacity ones I'm sticking with. I've finished Cryptography already and am 1/3 through learning python in CS1.

There is something dispiriting to me about a synchronous model. Once I can't keep up I tend to drop it as a failure, knowing there's no point in working through something that might be removed at any point. I also think it's the way I respond to the "don't break the chain" apps. Once life gets in the way and I do break the chain, I feel like a failure.

I'm quite happy to motivate myself however, so Udacity's model of giving the student however long they need, works perfectly.

I've signed up for over a dozen, finished three, learned significant amounts from, and done significant work in, about 5.