The Boards of Canada group hosted on Yahoo! Groups is a prominant BoC forum and one of oldest continously active BoC groups, dating back to 2000.
As time went on, mailing list spam became a larger and larger problem. With the group moderator inactive, there wasn't anyway to stop spam from getting to the list. In reponse to this, a new group, boards-of-canada, was formed on April 10, 2004 by bplotkin. While the previous group still exists, most discussion now occurs on this group.