I never set out to write serial stories, but it seems as though each one leads to the next. For example, once I told the story of Finally, My Love, I realized that the internet is a place where so many people meet that there must be a million stories in the naked www. So that led to PerfectPartners.com followed by Internet Romance Three, Who is that Woman? That one is not quite done.
Next I wrote Confessions from the Carnivore Club: Dave and Nancy's Story. Once I walked into the story, I knew that everyone I encountered had their own story. Barbara's story is coming next.
I think the advantage to short or novella length stories is that they lend themselves easily to this sort of serial. After all, I often want to hear more about the secondary characters in books I read. And this way, I get to hear all about them.