I think that I've read somewhere aroudn here how much feedback people have recieved, and I think that mnay have recieved feedback for threads they've added to other people's story. I can also imagine that many story creators choose to leave feedback for particularly good contributions to their stories.
I personally haven't recieved feedback for my threads or my story yet, and it's my impression that feedback isn't something that's given all that much. And I must admit that I haven't given any feedback myself. Rating threads and adding a couple of my own have so far been all I've done.
There are a couple of ways to get feedback within the Chyoo system.
If you write a thread for someone else's story, the story editor has to look at it and approve or deny it. This is an opportunity for them to write comments on it. The editor can also go back and add comments later to other people's threads after they've been approved.
Any signed-in user other than the author can rate a thread and may choose to add a short comment when rating. The rating and comment are anonymous unless you choose to write your name in the rating box. Often I will sign a rating comment. I've gotten more ratings without comment than with comments, and far more anonymous than signed comments. It took a while for feedback to show up for my threads, so be patient and write more threads. (I currently have 576 threads over several years, but only 107 feedback comments, if that gives you any sense of how often you might get them).
You can also ask for pre-submission feedback here on the forums, which could be useful when creating or contributing to your own story.
Likewise, I have 1014 threads and only 113 feedback comments. And 2342 ratings. I try to give comments along with my ratings. And Imhotep is outstanding at doing this for his stories.
In general, width is better than depth (ie; 3 storylines of 3 threads each beats one of 9), try to make your story into something relatively new and prepare to be patient, it might take a while before writers find your story (stories). Choose a standard for your story and stick with it, don't accept a 20-word thread because you're desperate.
Those are my improvised tips for the budding chyoo story-writer.