I have only been here a month, but I have read and seen many fiction hubs. If you want to write them, I would say go to it!
Also, to post a topic on the forum:
When you click the main forum link and are looking at recent threads, you have to choose one of the topic categories in the gray box on the left-hand side. Once you have landed within the appropriate topic category you will notice the "post a new topic" button near the top. Click that, choose a title/subject, type your question and you're good to go.