If you haven't taken the Stanford's Machine Learning MOOC by Prof Andrew Ng on Coursera, you are less likely to be taken seriously in the AI community. Or so they say.
Somewhere in 2008 Andrew Ng started the Stanford Engineering Everywhere (SEE) program that placed a number of Stanford courses online, for free. Andrew himself was responsible for teaching one of these courses, Machine Learning, which consisted of video lectures by him, along with the student materials used in the Stanford CS229 class.
The "applied" version of the Stanford class (CS229a) was hosted on ml-class.org and started in October 2011, with over 100,000 students registered for its first iteration; and became one of the first successful MOOCs made by Stanford professors.
Andrew Ng and Daphne Koller left Stanford to co-found Coursera in 2012. The Machine Learning course was one of the key offerings on the platform. And it continues to be #1 (check here, here, or comprehensively here).