The FanFiction subreddit is a general, informal community of people interested in fanfiction. They welcome you posting links to fanfiction you've written or to great fanfiction you've discovered. Topics range from how-to questions by newbies to high-level discussions about tropes and trends. It seems like pretty much everything is on the table, and the people who respond usually have interesting things to say. A friendly, intelligent, growing group.
FAN/FIC Magazine is a new online magazine for all things related to fanfiction and fanfiction culture, both the stuff that is traditionally published (i.e., based on public-doman works) and the vast universe of all the free fanfiction out there. Articles are high-quality and new ones are published on a frequent, regular basis. Access to the magazine is free, but if you believe in what they're trying to do: promote fanfiction, bring it into the mainstream, normalize it, and have intelligent discussions about it, then please donate to keep it going! All the contributors are paid for their work, and if you want to see more of this great, thought-provoking content, please chip in.