I was thinking in similar terms recently. Specifically about LJ emerging as probably the biggest mode of fic distribution these days. Arguably superceding mailing lists and archives. People make substantial efforts to ecourage feedbacking, establishing specific communities, etc. But what i remember as being remarcably effective is something practiced in comic fic a while back. Basically a fic equivalent to the quoting community on which metaquotes is based. Only it quoted humorous scenes from stories, rather than rl anecdotes