Also, for those who weren't previously acquainted: Ian was the "ian" in Debian, the Linux distro he created which is the basis for Ubuntu. He started work at Docker in November, which is why they are publishing this.
Debian and Slackware are the two oldest distros still around, beating out Red Hat by roughly a year. They form the inspiration and, in some key ways, the basis of many modern distros, and Debian especially created apt-get and greatly increased the number of people familiar with dependency-tracking package management. (I honestly can't find anything saying the Debian people invented dependency-tracking package managem…
Debian packaging was an amazing step forward in the Linux world when it appeared.