I have a PhD and I concluded a postdoc. Right now, while applying for a new postdoc or teaching positions, I have some months that are free. So, for example, I was considering taking a Coursera MOOC course taught by Google on Project Management.
I was wondering what is your opinion about MOOCs. If listing these kind of achievements has meaning to employers in the academic field, and in what case, so to understand whether it is worth doing it or not.
This would depend so much on your circumstances, it is hardly possible to give a good answer. You seem to have good academic credentials. Taking a Coursera course falls into the category: "has some experience with Project Management" or "is interested in Project Management". This is usually not important for a position where you are supposed to supervise graduate students, generate papers, and teach some undergraduates on the side without causing them to go to the dean. It is however important for positions that involve mainly teaching and exposure to current practices. A single coursera course is not going to make you an expert on project management, but if you are supposed to train software engineers and teach undergraduates, some demonstrated knowledge might be considered useful. How it would fit in with your profile is something I would not be able to tell.
Though I have only limited acquaintance with parts of academe where "project management" is a serious thing... I somehow doubt that (at least, in this year), on-line certifications will "impress" academic hiring committees. Indeed, conceivably, a candidate's world-view in which those (current) on-line things are perceived as worthwhile might be viewed as a negative.
E.g., in my field, mathematics, if/when prospective grad students talk about what they've seen at "Khan Academy" (a popular, but very low-level and glib thing), or about their blog, or about their reading of other blogs, ... it tends to make me think they don't understand the somewhat-serious enterprise of modern mathematics. Yes, of course, younger people do not have experience... and can't be blamed... but, still, the worlds of professional this-and-that do not seem to be adequately mirrored in "on-line courses".
