Hmm... I hadn't really thought about the non-pg issue. Not sure how to handle that. Let me think on that.
I would recommend allowing moderators to use their discretion and allowing material that is tastefully non-pg. IE, if the story is legitimately sharing a funny experience of coupled or shared space life and isn't just pornographic.
It's a solid implementation, though the design is nothing spectacular, it's not an eye sore either and does the job. The one thing I would suggest is allowing comments - but using a solid moderation hand.
One question though, will you allow stories of a non-pg nature?