lj_feedback: A place for us to solicit opinions by posting polls, surveys, and questions.
paidmembers: Information specific to paid members: sneak peeks at new features and special LJ-specific account offers.
lj_maintenance: Messages from our Operations staff about downtime -- planned or unplanned! -- and scheduled maintenance.
lj_releases: A running list of all changes to the site, bugfixes and enhancements.
news: LiveJournal's official community for news, notes, and quotes about anything LiveJournal.
remixed: LiveJournal's creative contest community.
simplynews: A simulcast news community featuring text-only entries from the official LiveJournal community.