Well, this FAQ, among other things :-) Accord-Fic-L began as an informal review group for the story "Privileges of Rank" and grew into a general discussion not only of Accord fiction but of how to coordinate related fictional universes, specifically Avenger and Shadowstar Station. It basically serves not so much as an editorial board as a venue where the Accord Fiction editor (Doc Kinne), the Avenger Fiction editor (Alex Rosenzweig), the Shadowstar Fiction editor (Rahadyan Sastrowardoyo) and other interested parties can discuss, debate and outright argue the shape of their respective universes and the areas they share.
Topics range from comments on specific stories-in-progress (in this sense, it's a writer's workshop) to all the geeky questions that make up Trek fandom (canon vs. non-canon, details of astrocartography, politics, where Trek and real-life differ and which we should use for our own universes, etc).
While not exclusive, per se, the list members wish to keep active membership relatively low in order to keep the discussion manageable. If you have a serious interest in the shape of Accord or shared fiction and you're a member of Accord, Avenger or Shadowstar, you should contact Doc Kinne, the Accord Fiction Editor.
If you do wind up joining the list, there are basically only two rules: 1] Be polite. We're all friends here. 2] The Editor is Always Right; which is to say that while the group can debate and discuss, the final decision for each universe is ultimately made by the editor for that universe, and will not be put to a vote. The group is advisory, not democratic in nature.
USS Accord is a direct off-shoot of USS Avenger in real life, and has elected to be a direct off-shoot in fiction, as well. As should be clear from the character sketches above, USS Accord's command staff began their fictional careers on USS Avenger, either as officers of that ship, as officers of the "Accord" Training Cadre (in real life, Shuttle Accord, the provisional form of the Accord chapter), or as members of the Accord Refit Team. In particular, Mike Shappe and Mark Anbinder were both Division Chiefs (Engineering and Communications, respectively) on Avenger.
Shadowstar Station is an indirect off-shoot of USS Avenger, deriving directly from USS Sovereign, one of Avenger's other children. Shadowstar chose to play in about the same time period Accord and Avenger chose to, and there are commonalities (deliberately introduced) between Shadowstar's backstory and Avenger's.
All three groups play in the late 23d century, just after Star Trek: The Undiscovered Country, and have similar philosophies regarding fictionalizing their chapters. There are a few incompatibilities (the most noticable being that Avenger's universe does not have a Star Fleet Marine Corps in it; on the other hand, no Avenger Fiction story explicitly denies the existence of marines), but by and large, the three mesh well - better since they began coordinating actively. Several other chapters whose stories are based in the mid 24th century (TNG era) have mentioned or used Shadowstar station, so it is assumed that the facility survives for a good long time.
All three universes come together to some degree in the in-progress Accord novel That Which Does Not Kill Us Makes Us Stronger, in which Avenger's Admiral Alex Rosenzweig appears as a major character, and several events occur at Shadowstar Station. That story also pulls in Commodore Bob Vosseller, Commandant of the Seventh Fleet and CO of USS Challenger, despite the fact that Challenger's own fiction takes place in the TNG time-frame. So, while the character and USS Challenger are used (to mesh with the real Region Seven), Accord and Challenger Fiction are not linked.