About me: I used to be a regular on some (pen and paper) game fora, but I haven't been involved in forum life lately. Before Cake started, I did miss the kind of conversations that used to sometimes crop up in the comments of my (now defunct) personal blog -- more discursive and cozy than twitter or my other current haunts.
I'm a fiction writer. All my published work is short form, most of it science fiction. I haven't been getting new work out regularly for a few years as I've been working on novel manuscripts.
About Cake: I second what @JazliAziz said above about ending your initial post with a question to encourage people to respond! This post I made yesterday, now that I think about it, is a good example of what I instinctively tend toward in opening a topic: https://www.cake.co/conversations/zWHBK40/how-do-you-discover-new-books-and-authors
It's short, but it has a basic form of:
0. Title: topic/question
1. Why I think this is interesting or important
2. Sharing my own perspective or example
3. Restatement of question, preferably with a few offshoot questions to encourage lateral answers
I definitely like to end with a question to open the discussion up and prompt people to talk about themselves, but I think it helps encourage that if you give your own contribution/answer first. It's like putting a dollar in the tip jar at the beginning of the day -- it sets the example and gets things going!
I also try for clarity -- in longer form conversation like this, someone can get going pretty far on the wrong foot before you go 'oh, that isn't what I meant!' Formatting helps understanding: I use headings or emphasize important words, as well as breaking up long paragraphs and using inline photos in long posts. I probably should have busted up the middle paragraph in that book post into bullet points! Chunks of text can tire the eye.
Finally, make sure to read over your post before you make it. On Cake, you can edit, but it's good to just do one more pass for clarity -- and since on Cake I'm writing in an informal voice, I often have to take out a lot of boring or weasel words that make my sentences longer at the expense of directness.