Yuletide has two official communities.
Yuletide: The main Yuletide community. The community allows posts by any participants and enjoyers of Yuletide, as long as they follow the community rules. During Yuletide season many people create posts for things such as brainstorming, general questions, writen-ins, and recommendations. When it is not Yuletide season, community activity is generally limited to digests that the mods post listing recently published New Year's Resolutions stories.
Yuletide-Admin: A community dedicated only to administrative announcements. Important updates (such as when nominations open, when sign-ups open, and when things close) are posted here, though they might be posted in the main community as well.
Yuletide has several unofficial communities that have been created over the years.
YT Unofficial: Created in 2011 as a place to discuss anything Yuletide, in response to the fact the official Yuletide community discourages and deletes certain discussions about the exchange. Participants can post using either their actual journal or a sock puppet, and comments can be anonymous or not.
Yuletide Coal: Anonymous meme created in 2010 to complain about gifts received. Eventually the community expanded to voice complaints about all the various facets of Yuletide.
Yuletide Nudge: A community that serves to give encouragment during the Yuletide writing process.
In addition, sometimes discussions about Yuletide show up on the anonymous meme fail_fandomanon.