Artemis Project and Moon Society Meeting Server: Chat system used by the Moon Society and Artemis project for online discussions - busy most evenings.
Artemis Project General Mailing List: Discussion of return to the Moon. Moderated by leadership of Artemis Society International.
Dave Dietzler's BBS: Kardashev levels, colonizing the asteroids and comets, general essays and discussion on space development and colonization.
Frontier Files Online || Opening the Space Frontier: Relaunched community blog - space-related press releases, general developments on the space frontier.
HobbySpace: Space log tracks developments in space commercialization particularly; occasional interviews and other newsworthy items.
Lunar News Network: Blog on US space program focused on return to the Moon.
Moon Society Yahoo group: Open discussion group moderated by Moon Society leaders.
National Space Society Forums: Forums focused on the NSS roadmap to space settlement, and activities of NSS chapters.
New Mars Forums: Mars Society Newsletter Online Forums
Out of the Cradle: Blog chronicling the new space age: news, interviews, and reviews on all aspects of space development.
RocketForge :: A Blog for the Space Age: Amateur rocketry, the X prize, and our purpose in settling space.
Selenian Boondocks: Blog on new space companies and lunar colonization; the inside scoop on commercial space from Jonathan Goff and Ken Murphy.
Space Sciences -- HabitableZone: Hot topics from the latest space missions, and where we should go next.
Space-architecture list: Discussions on building things in space.
Space-elevator forum: Mailing list for discussion of space elevators, in theory and practice.
SpaceADG mailing list: Space exploration science, history and current events. Focus is primarily on NASA space activities.
Spacesettlers forum: Mailing list for discussion of settling space.
SSI_list: Mailing list for the space studies institute (SSI) - general discussion of space development, space solar power, and O'Neill-style habitats.
Yahoo! Groups : GreenCELSSTaskFORCE: Dedicated to creating self-sustaining closed-loop environments (only input: sunlight).