I'm really happy to read you came to the same conclusions!
I'm new to your platform, so it might be too soon to be able to give any feedback, but I already like that you let us add a canonical URL to our Front Matter, and provide a way to create post drafts from a feed.
I see you also provide a feed for my content, so people can use your platform as a source, and POSSE anywhere else.
To really be interesting for POSSE, through, you would have to provide users with the ability to use their own domain. It's the only way they can start publishing there, and be free to move elsewhere later, without losing all canonical URLs they would have put on other platforms.
Not specific to POSSE, I really like the fact you give us a Markdown editor instead of a shiny but very limited WYSIWYG editor. It gives us more features, similar to what we find everywhere in our projects nowadays. We can feel more at home here, thanks to this.
Great to hear the feedback.
Re: Domains, I've always thought of this as sort of an antipattern from a pure technical perspective, especially with things like serviceworkers which really scope to a domain, but always willing to continually have this conversation.
On that note, we will be open-sourcing our code and have the theoretical notion of a decentralized-but-compatible web of similar platforms. We don't have any designs to go too hard into this arena on day one, but it's an idea we're keeping around as a strong possibility.
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.