<s>Let's get a blog post up about the captions release, published shorty after we're stable in production, late October 2018.
The audience for the blog post is the Wikimedia community as well as GLAM partners in the SDC project, plus anyone else interested in linked data.
I've contacted comms to get this into their pipeline.</s>
We're going to write a "big picture" narrative post for the first feature releases for Commons - captions, depicts, other statements. Publishing time is TBD.