After Quincy (the Founder of freeCodeCamp) mentioned the eBook, it got a lot of traction. Had 40+ sales during the night and managed to get to 200 total sales before the 48 hour mark hit.
I also noticed that sharing the updates is bringing in a lot of impressions and a few sales, every time.
Also, I had an AMA last night on Twitter where people could ask me anything about my journey. I'm thinking that it also helped get a few sales.