I couldn't remember when I joined, but it turns out 2014 too. From that date and dang's comment below, I found the HN submission that motivated me to join:
https://news.ycombinator.com/item?id=7550005
This is where I learned about Watsi - https://www.youtube.com/watch?v=WlT3UhC7NwQ
I attended it in person. Very inspiring!
I couldn't remember when I joined, but it turns out 2014 too. From that date and dang's comment below, I found the HN submission that motivated me to join:
https://news.ycombinator.com/item?id=7550005