The course timing is up to you. But there are deadlines for assignments or exams (if available). Expect to spend about 4-6 hours per week for lectures, and additional hours to complete the assignments and quizzes.

The classes are conducted like web training. The interaction is one way only, however they might schedule a life conference depending on the course. You are also encouraged to participate in the forum.

Upon completion of the course, they may issue you a certificate of completion.

Another alternative to Coursera, edX (https://www.edx.org/).

Some participating universities:
MIT
Berkeley
Harvard

Yes. but the assignments are multiple choice. They won't have time to personally mark your paper since the student numbers are in the tens of thousands.

You can, if it's really relevant to your scope of work. List it as additional training. Some of the Universities provide a certificate you can print out. Since these are really reputable universities, it sounds good on your resume.

Edit: It also shows that you are constantly improving your knowledge, which is never a bad thing.

This post has been edited by evolove15: Feb 25 2013, 01:48 PM