Plus stories fare better or worse depending on the category. Loving Wives and Incest/Taboo get quite a few hits. Romance stories/Erotic Couplings float about in the middle somewhere. Graveyard categories - Novels and Novellas (unless you've got a bit of a following) and Letters and Transcripts...
On SOL, where I've been mostly publishing, every story is a complete adventure. Sometimes one of my better stories will disappear off of the radar so fast that virtually no one read it. Other time, some piece of dreck that I just tossed up gets high downloads for nearly a week. It all depends upon the phase of the moon. Also avoid posting holiday three-day weekends.