In a comment under my last piece, Drew Kime asks a question that needs asking.
"What is it about WordPress that you see as siloed?"
The answer might surprise you. Nothing. WordPress is silo-free.
It has an open API. A couple of them.
It's a good API. I know, because I designed the first one.
WordPress is open source.
Users can download their data.
It supports RSS.
"So, if WordPress is silo-free, there must be something about MyWord that makes it worth doing, or you wouldn't be doing it," I can imagine Mr Kime asking, as a follow-up.
Silo-free is not enough
This question also came up in Phil Windley's latest MyWord post, where he introduced the editor with: "I can see you yawning. You're thinking 'Another blogging tool? Spare me!'" He went on to explain how MWE is radically silo-free.
But there's another reason I'm doing the MyWord blogging platform, which I explained in a comment.
MyWord Editor is going to be competitive in ease-of-use and power with the other blogging systems. The reason to use it won't be the unique architecture, for most people. It'll be that it's the best blogging system. This is something I know about, and I'm not happy with the way blogging tools have evolved.
The pull-quote: "I'm not happy with the way blogging tools have evolved."
Imagine if you took Medium, added features so it was a complete blogging system, and made it radically silo-free, and then add more features that amount to some of the evolution blogging would have made during its frozen period, the last ten years or so, and you'll have a pretty good idea of what I want to do with MWE.
Blogging is frozen
There haven't been new features in blogging in a long time. Where's the excitement? It looks to me like there's been no effort made to factor the user interface, to simplify and group functionality so the first-time user isn't confronted with the full feature set, left on his or her own to figure out where to go to create a new post or edit an existing one. Blogging platforms can be both easier and more powerful, I know because I've made blogging platforms that were.
Basically I got tired of waiting for today's blogging world to catch up to 2002. I figured out what was needed to win, and then set about doing it.
I have no ambition to start a company. I like to make software. I'm happy to keep going as we have been going. I think JavaScript is a wonderful platform, with apps running in the browser, and in Node.js on the server. It's a more fluid technology world today than it was in 2002 the last time I shipped a blogging platform.
I would also happily team up with companies who think this is a great opportunity. That blogging has stagnated too long, and that there must be ways to reinvigorate the market. I don't like taking shots at WordPress, but honestly I think it's stuck. I'm happy to talk with entrepreneurs who have ideas on how to create money-making businesses from an exciting user-oriented, user-empowering, radically silo-free open source blogging platform! Blogging needs a kick in the butt. I propose to give it one. With love. 
Anyway, to Drew, thanks for asking the question. I doubt if you were expecting this much of an answer, but the question needed asking, and I wanted to answer it.
PS: Here's an idea of what a MyWord post looks like.