You wrote: 

Oh, what the hell - I'll do it.  But I missed last year so what 
exactly happens on a fanfic pannel?

We ritually sacrifice you to the fanfic gods.  :-)

It's nothing complicated.  It's just a forum for discussing fanfic: 
what's popular, what's not, writing techniques, publishing tips, 
anything that has to do with the medium.  The audience is usually a mix 
of readers and writers; last year it was mostly writers.  It's fun and 
a good way to promote your work.

------RM