NoNane: You reminded me of two places that I think always did a good job of linking updates to the forums– CBR (comic book resources/reviews) and the old AnimeNewsNetwork.com page. Example — see review post and bottom link to “Comments” aka the specific forum thread? http://www.comicbookresources.com/?page=user_review&id=6728
And for an example of an integrated forum/social login — see http://www.momocon.com/wp-login.php?action=register . That still allows you to watch commentors but with that option makes it easier for community members to get in/out of a forum .
As for the author community — I’m not quite sure exactly how to nail down serial writers. There’s some that manage to find Goodreads (there is one group there) and some end up at Webfiction Guide . The paths between don’t intersect very much but certainly there are far more authors at Goodreads than other places I frequent.
Would any of the creative (prose) folks wish to guest blog or something at online-novel.com about what you are hoping to find? While I don’t usually like flat out commercial posts, I’m open to smart content that provides some insight into your challenges (as you look through the slush pile) and obvious links to what you’re working on. If yes, let me know and I’ll set up a guest account for drafting of a post. Usually my only edits are to suggest things like social network links or clarify things I don’t quite get. (CA Sanders probably handles it best — see http://theonlinenovel.wordpress.com/author/craigasanders/ ) Let me know!