The guild title area within the World of Warcraft forums does not match the armory, nor in-game character’s guild they are in.
For example, when I made a post tonight in the forum topic located in “Forums > PvP > Battlegrounds > Feedback: Epic Battlegrounds” the guild name next to my character’s post inside the forum topic did not match the guild I am in via the armory, nor in-game. The post showed I was in the guild “Warbringer”, when I’m actually in the guild “Clan Battlehammer”.