While that may be a shock for some viewers, it's hardly a surprise. Never a ratings winner for the network, the show still maintained a loyal and supportive fan base, which even began the #SixSeasonsAndAMovie Twitter campaign after Community went on hiatus in 2011. After struggling to find its place among NBC's more mainstream comedy lineup and bouncing around highly competitive time slots, the show also faced fallout from its topsy-turvy fourth season when creator Dan Harmon was replaced as Community's showrunner. Harmon returned for the fifth season, which saw a boost in viewership but a small decline in ratings.
After news of the cancelation broke today, Community star Joel McHale tweeted "#darkesttimeline," a reference to an episode from the third season.
Some have speculated that this won't be the end, and that Community could find another home on a cable or streaming-video service like Netflix or Hulu. But, for now, class is dismissed. (EW)