Jason, thank you for your feedback and suggestions on how to post on Cake.
TLDR Cake isn't Facebook, or a Medium killer. It is built for great conversations on any topic.
I'm a designer here at Cake and will try to answer your questions:
1) Put the post content section directly inline with content (top center of the content body).
On Facebook and other social platforms you can comment on anything right in the feed, without needing to see the whole post or any of the comments on it. This allows for a "quick engagement" where you can immediately post without reading. It comes at a price, for the readers as they'll have to sift through the noise.
On Cake's feed we show titles of conversations, not individual posts. Which is why people can't immediately post from the feed. We did that to discourage people from posting in conversations just by reading the title. Instead they have to dive into a conversation in order to post. Hopefully by doing so they'll at least read some of the posts before jumping into a discussion. This way the conversation evolves and gets better with each post rather than become fragmented by random posts.
2) Publish or Post button should be under the content the user created.
When starting a conversation, we put "Publish" in the upper right corner to allow for the maximum real estate for the person to craft their first post. When posting in a conversation we've also put the "Post" button at the top of the postbar. We actually had it at the bottom, but after using it for a while it proved to take up too much space away from crafting a post. This problem is especially apparent on mobile, where the virtual keyboard takes up a lot of the screen.
3) Allow hashtags inline with the text of posts for categories or subjects instead of requiring the user add them in some magic hidden space above the editor.
In places like Instagram, hashtags don't have as much meaning or importance as they do here on Cake. Early on we decided that Cake will be designed around topics and we'll have to limit their number for each conversation. We started with 3, but eventually settled on 5 topics. Any more than that and it becomes messy, diminishes the value of each topic and encourages spamming other topics. Since only conversations, not individual posts can have topics associated with them, it makes navigating between topics and discovering conversations much easier.
Is Cake long form, social media, a Medium clone, or a Facebook killer?
Let me assure you it's not a Facebook killer. Why? How do I find, follow or invite friends?
We never intended nor want to become a Facebook killer. There is a fundamental utility in Facebook, which is to keep in touch with friends and family and follow each other. The flip side is that your friends and family don't always share you interests. This is why we built Cake, you are here to have great conversation with people like yourself, who are interested in the same things. On Cake you don't follow people, you follow topics. As such, we haven't built tools like importing your contact list or searching for your friends. Maybe we'll do some of that in the future as out team grows and we hear the need for it, but this isn't a priority.
Right now it's like a much less popular Medium with fewer features.
If the intent is to publish articles then Cake isn't great for that and Medium is far better. Cake is built for ongoing conversation with each posts building on top of the other, just like you would when talking to someone in real life.
Here is an analogy: Medium is for lectures while Cake is for conversations.
To prove my point, if you had published this on Medium, everything I just wrote would have been buried in a comments sections at the bottom of the article. But here we can continue debating Cake's pros, cons and fit for everyone to enjoy reading. After all this conversation can keep on evolving, while the article, once published, is done.