This was actually only the second annual World Bipolar Day, that's probably why it's not well-known yet. It was started in 2014 by the Asian Network for Bipolar Disorders (I think that's the name) and the International Bipolar Foundation which is based in San Diego, CA. The purpose is to raise awareness, educate, and "normalize" the illness to help dispel the stigma. I posted a brief blurb about this on my blog yesterday.