Own your content, or be read.

In the piece Own your words, Matt Gemmell argues that you should keep your content on your own site:

I do have an issue with giving away your words just because it’s easy to do so. By default, your words should be yours, and that means more than being attributed: it also means gathering them together in your own publication, controlled by you, that serves as a place for your own voice to be heard above (and instead of) all others.

Matt has a popular blog with many readers. For most other people, the choice between publishing on Facebook, a site like Medium, or on their personal blog, often comes down to the vanity metric: How many people will read my words?