Well, per default nothing writen by the users will be canon. If it is very good it might become canon in the future, who knows. But like with things such as Star Wars, Star Trek and other things, it's fine to write what ever you want.
Personally, I was going to write how my trade-empire was burned to ashes by an alien race (the Azsendi) after a trade dispute with them escalated to full scale war. The focus of my story would be the about the life and rise of Berend Karling through the ranks to his eventual becoming High Chancellor and leader of a new growing empire. My stories are usually very detailed and have a "realistic" dark atmosphere about them.
Writing this I really want to start doing that again, I've got loads of plans
. If I do start it again in the evenings I'll post it here. (while making clear that there is a "absolutely-no-canon" sticker on it xD)