A very interesting post here:

There’s an internet rule called 1%-9%-90% which states 1% create, 9% comment/interact/curate, 90% consume. Let me borrow this construct and apply it specifically to web publishing:

• WordPress is for the 1%. There are content creators who want their own dry piece of land, a full featured CMS and total control over their blog. I am one of these people. These folks also are happy to deal with their own content promotion and try to build an audience. They construct their own themes and topics to write about, and most of the content is original to them.
• Medium is for the 9%. These people want to write but don’t want to maintain a blog (hence the publishing tool and centralized namespace). They sometimes need inspiration or to feel like part of something bigger (hence collections). They aren’t focused on driving their own traffic (hence promotion). They don’t want to blog daily or necessarily establish an ongoing readership. They like feedback (hence comments) but don’t want to get into flame wars.
• Tumblr is for the 90%. The masses want to collect, comment and republish other people’s assets. They use Tumblr to express themselves. They’re part of a community and the content they create gets pushed and reblogged via Tumblr Dashboard. Most of the content is not fully original (that’s not to say there isn’t unique content on Tumblr or that the remixing itself isn’t highly creative, more so that if you look at Tumblr in its entirety – not just the popular hipster urls – it’s a lot of YouTube videos, imgur pics, etc. Not a judgment).

Succinctly, Medium occupies the space in-between WordPress and Tumblr. A creative space that’s less complex than a CMS but more geared towards writing original medium-longform content than Tumblr.

http://hunterwalk.com/2013/10/23/ev-williams-medium-is-blogging-for-the-9/