Longer is not inately better for humor threads, even ones surrounding the same topic. Because people stop responding epic. They read and they laugh and they stop responding and the humor posts eventually are right next to each other with maybe one or two people posting between. Are you going to doubt me on that? These aren't threads for discussion or even chatting, they are threads for humor and as such shorter is better. There is not a single mold you can force every thread into.