Filk is definitely appropriate for the community! I've tried to use "fanworks" instead of "stories" as much as I can but I have probably slipped up. Anyway, yes filk.

A pointer to something else usually doesn't work as a discussion starter, since people just follow the link offsite and don't really have anything to say, but a pointer + a question like "do you have any other good filk-related links" or "what's your favorite filk" or "how would you define filk" or "what's an interesting memory you have involving filk" would probably work!