Fan Nickname: Anything related to the fic is bound to be called "Big Damn X".
For example, the "Big Damn Harem" which consists currently of all of the girls of the SOS Brigade, and the Big Damn VN Brigade who are the people responsible for making the Kinetic Novel.
Jossed: The tenth and eleventh novels Jossed pretty much everything introduced for this fic, including the motivations of certain characters and absolutely everything about the OC Stand In. Fortunately, the writer always intended Big Damn Hero to be an Alternate Universe Fic, so he is still writing it regardless of these setbacks.
Recent chapters seem to be written around novels 10 and 11 to a degree, slipping in details from the novels that the fic hadn't previously contradicted (like Sasaki previously going to Haruhi's elementary school) and explaining away at least one contradiction despite the alternate universe premise (Koizumi mentions that Tachibana was under the mistaken impression that he was the Organization's leader).
One of Us: The author peppers his story with tropes, and explicitly stated it's a TV Tropes crossover.
Why Fandom Can't Have Nice Things: Played straight and inverted at the same time: the reason that Durandall has left Fanfiction.net, and thus stopped posting new chapters and reviewing fan fiction there, is because of the criticism of his viewpoints in his reviews towards other fanfic authors on the site.