I would not list it under "Education" alongside a formal degree. However, I might mention it in a cover letter to demonstrate passion and internal motivation for a given subject.

While I'm quick to condemn certification, I can see the other side of this argument as well. To a lot of people, Coursera represents the opportunity to overhaul a broken education system. In order for true change, Coursera must not only demonstrate that it can educate people, but that it can do so credibly and consistently.