"Community" was also nominated for TCA Award for Outstanding Achievement in Comedy at the 2012 TCA Awards. While sitcoms are often underrepresented in the academic study of television, "Community" is an exception. More specifically, television critics and scholars often reference "Community" when discussing semiotics, the study of signs, in television and film. Television itself does not convey meaning, but rather viewers construct meaning based on recognizable signs and references, so a complex show like "Community" is rich with potential semiotic analysis. Some critics have even claimed that the show itself is about semiotics. Mordicai Knode of Tor.com suggests the show is "about the tropes of every single genre, it is about the cinematic language and the shared culture we all bring piecemeal to the table when we sit down as audiences." Dan Harmon fills each episode with signs and references in order for the audience to deconstruct and construct their own meaning, even going so far as to break the fourth wall to give viewers a wink and a nod to the show's complexity. Fans of "Community" require a "certain level of rhetorical and interpretive skills" to pick up on these semiotic layers of the series:"The most important knowledge a viewer brings to the viewing of Community is the subconscious recognition of indicators for other formal systems (meaning other genres or specific texts) with help from subconscious hypotheses and charts that are built on previous experiences with similar works." Premiering in the 9:30 pm ET spot on September 17, 2009, the pilot episode had a viewership of 7.680 million. In the 18–49 audience, it had a rating of 3.7. As such, it held 93% of this audience from "The Office", which had been in the previous time slot. The show was called the "bright spot for the night" for NBC, seeing how "The Office" was down 18% from the previous year's premiere, while "Parks and Recreation", in the preceding time slot, was down 30%. However, the show, like many other NBC comedies at the time (including "The Office", "Parks and Recreation", and "30 Rock"), would later struggle in the ratings despite critical acclaim, though the show did tend to improve after factoring in DVR ratings. Some commentators noted that the show's uniqueness and ambition prevented it from achieving the broad appeal of other sitcoms. Seasonal rankings (based on average total viewers per episode) of "Community": Note: "Each U.S. network television season starts in late September and ends in late May, which coincides with the completion of May sweeps."