This has been posted to HN 19+ times, here are some of the more useful threads:
https://news.ycombinator.com/item?id=14191577
https://news.ycombinator.com/item?id=20751074
https://news.ycombinator.com/item?id=11402656
https://news.ycombinator.com/item?id=12503851
https://news.ycombinator.com/item?id=8804691
https://news.ycombinator.com/item?id=30100427
https://news.ycombinator.com/item?id=28686939
https://news.ycombinator.com/item?id=17803451