I'm very glad to earn my first certificate from Coursera.org, for the course Networked Life delivred by Michael kearns, University of Pennsylvania.
i've got a score of 94%
you can find my notes of this course here
I've attended the class Power searching with Google (September -October session). At the beginning, it was for fun. But i've realised that my search queries have improved a lot using the tips learnt from this course. And you know what, i'm happy to get my Certificate :-)
You can check my notes of the course here.