The migration to Insane Journal and Dreamwidth a few years ago split up the old LJ media fanbase quite a bit, and Tumblr and Twitter are getting a lot of fannish activity as well. My current fandom blew up in early 2012 and is almost exclusively on Twitter/Tumblr, with fic being posted on AO3. There's not a lot of meta discussion, though, of the sort that would have happened on LJ.