I assume you are speaking of questions, needing more space for answers? When you are answering a question, you can write a hub about it. Just click the link at the bottom of your answer box marked "make a Hub about it". That will link the hub to your answer here and it can be as long as you like.
If you are speaking of commenting in a hub, you have a considerable comment block that is available. Or you can write a hub about it. That is, of course, the reason for the site.