There was a talk about Node.js at Open Source Bridge in Portland in 2011 or 2012 (nice con). I was volunteering doing mic handling at that talk.

I remember the speaker saying about how they had no idea about how to debug node programs. My personal reaction was that this was a fun little toy, but the idea of JS on the backend was utter madness. Little did I know what a monster it would become.

For the record I still think JS on the backend (or anywhere else) is madness.

Indeed, it is often amazing to me to see what catches on and what doesn't. However, the concept of cooperative, event-based processing coupled with an existing and popular language is probably what was decisive wrt Node.js.