Medium is on its way to becoming the consensus platform for writing on the web. if you’re not sure you’re going to be blogging regularly, the default place to put your writing is Medium, rather than starting a blog on Tumblr or WordPress.com, for example.
A post from Dave Winer regarding the dominance of Medium and the importance of protecting the open web. Personally, it has never crossed my mind to use Medium, but I think I can understand the appeal. Interesting that Dave syndicates his own content to Medium.