The Anchor
The Consensus tabard currently features an anchor, which was chosen as an homage to Jaina Proudmoore, who, throughout Warcraft lore, consistently represents the Alliance at its best through her dedication to the ideals of respect and mutual understanding. The stronghold she rules over, Theramore, prominently features an anchor in its banner, which itself is inherited from Jaina's father's home nation of Kul Tiras.
In addition to the homage, however, the anchor was also chosen because it is symbolic of home, and also because it's a simple design that's easily reproducible on any medium.
The flag featured on the Consensus website banner is actually the Kul Tiras flag, and was originally taken from Warcraft II. A link to the original image on WoWWiki can be found here.
Since its inception as the symbol of Consensus, the anchor has inspired a nautical theme for the guild; members are known to refer to the community as the "SS Consensus", for example, and many of the Ventrilo rooms are named after parts of a ship.
