I did some searches but couldn't find anything. If someone else does and the thread is closed for replying, let me know at hn@ycombinator.com and I'll reopen it.

If anyone can find this I'd be very grateful, would be cool to read his comments

Tried Googling "mackay site:news.ycombinator.com" and found a lot of times where this book has been mentioned; I didn't see anything that clearly said "I am David Mackay" but that might be a good start.

(You'll also find the occasional reference to Charles Mackay's book Extraordinary Popular Delusions and the Madness of Crowds.)