It's very nicely done, and looks like it's easy to use, but it's a silo.
If you write there, you're performing for free.
If it works, the owners will make a billion dollars. Good for them. Not great for us.
Because it's owned, if it's successful, we'll be "users" and others will be "partners."
It's not a level playing field now, and if it were to get successful, it will very likely become less of one.
I am writing this in an outliner.
I envision a day when you have an outliner too, and will be able to put the cursor on a line you want to write relative to, right click, and glue that spot to a spot in your outline. Start writing. And your writing will appear under mine in my world. Also in your world.
I want to do another bootstrap. Writing inside someone's silo might help them bootstrap yet another silo. Not only is that boring, but it is against my interest.
I want a wild disorganized chaotic brainstorming space that spans the world, open to everyone.
Not a place for Dick Costolo and Ev Williams to bring my eyeballs to Pepsi and Nascar.
Those guys tend to think in terms of insiders and outsiders. I think that's weak.
I'm using Disqus for the comments here. But this is a bootstrap too. I do it this way because...
1. You don't need to install any software to participate.