Someone suggested giving the user the chance to write a post with no category. And another someone suggested using keywords for posts. But I think no one has suggested what I would like: the possibility to create a category at the "write post" screen. You see, many times I start writing a post and then notice I haven't created the appropriate category for it. Well, if there was a button in that screen, below the list of existing categories, to create a new one, life would be easier at those times. Now, I only have two options: (a) discard the post, go to the "Categories" tab, create the new category, and rewrite the post, or (b) post to any wrong category, go to the "Categories" tab, create the new category, go to the "Posts" tab, edit the last post, and change its category. Too messy, and I think it wouldn't be that hard to code that button. But maybe I'm wrong.