The class is made up of video lectures, usually 10-15 minutes long, posted each week. The lectures are usually split in modules making it easy to break up your work on the class in small chunks. You do not have to lock up 2-3 consecutive hours to get the class down. I break up my work in small chunks based on free time.
MOOCs or massive open online courses have been around for a little while. They are a great way to start learning something new or increase your knowledge in a field you know well already. Sometimes just the collaboration with other students and having to do reading and homework is a great way to keep your brain sharp.
I may have a few more posts about this course in particular.