Asexual Awareness Week: An awareness campaign that does more than pop up once a year; education and campaign information is available through their website, including pamphlets and resources.
Partnership for Asexual Visibility and Education (PAVE): An organization dedicated to the political and activist aspects of the asexual community and its allies. (Mission statement includes Distribution, Development, and Coalition.)
APositive.org: Discussion of research and knowledge about the orientation, open to both asexual and allied/interested.
Everything's A-Okay: Companion website for the YouTube video channel, aiming to educate about the ace spectrum.
Demi Grace: A forum home for demisexuals, grey-asexuals, and allies.
Demisexuality.org: All about demisexuality, an orientation that has a lot in common with asexuality and is considered to be on the asexual spectrum.
Transyada forums: "Messing around with gender since 2010." This place originated from a gender subforum on AVEN.
Asexual & Kinky and Ace BDSM Support Group: Fetlife is a fetish community that is asexual-friendly and has support groups specifically for asexual people if they are kinksters.
The Asexual Agenda: More 201-level discussion of asexuality, on a blog with multiple contributors.
Asexual Advice Tumblr: This blog takes submissions from readers, using a team of volunteer asexual people who are experienced in answering questions.
Resources for Asexual Survivors: An organization for and by asexual survivors of sexual violence to help others in similar situations.