Interesting improvements. Custom domain name hosting like what's offered by Wordpress and Tumblr.
Medium released a publishing API.
Medium - On-publishing - Jul 29, 2013
Examples of nicely formatted Medium.com stories - Apr 05, 2014
Medium - I.M.H.O - Jul 29, 2013
Medium - Writers on Writing - Jul 29, 2013
Medium - Help Center - Jul 29, 2013