I hadn't seen any discussion or mention on HN. This is an important milestone in increasing the availability of space, both for commercial and human ventures, and possibly for extraglobal habitation in the future.

I found the WaitButWhy series on Musk and his companies to be interesting and enlightening (as someone with no aerospace background):

Part 1: http://waitbutwhy.com/2015/05/elon-musk-the-worlds-raddest-m...

The SpaceX post (part 3): http://waitbutwhy.com/2015/08/how-and-why-spacex-will-coloni...

Additional SpaceX post: http://waitbutwhy.com/2016/09/spacexs-big-fking-rocket-the-f...

Edit: line breaks for links.