The courses are interesting, one can take a course for free and then if one likes it sign up to get credit. Remember, how in university or college, you'd often drop a course or take a different one after going to a few sessions. It's even easier with EdX. One can take a course completely for free or, decide that one wants credit after up to a reasonable point in time, that's normally a few weeks into the course, or later! I'm looking into a few subjects that I could have made a career of, but, one only has one life. It's great to learn about other things, too!
