Interesting improvements. Custom domain name hosting like what's offered by Wordpress and Tumblr.
Medium released a publishing API.
Scaup JSON Descriptions - Apr 17, 2015
Medium - Jobs - Jul 29, 2013
Medium - Medium Ideas - Jul 29, 2013
Examples of nicely formatted Medium.com stories - Apr 05, 2014
Medium - On-publishing - Jul 29, 2013