Variety is careful to mention that there is a possibility the last episode didn't air because of the content, and not because the show is cancelled. But they call out the terrible ratings it's getting, so it looks like the writing is on the wall.
Fox, meanwhile, opted to yank the remaining episode of "Sit Down, Shut Up" after the show posted a dismal 0.7 rating/3 share among adults 18-49.
But it's believed the show may have also been pulled this Sunday due to some content concerns -- particularly since "Sit Down" airs at 7 p.m. Fox will run a repeat "King of the Hill" in that slot.
Given "Sit Down's" perf, the animated half-hour is not expected to return.
The funny thing about all this is I was really excited when I heard about this show and also NBC's Parks and Recreation because of the people involved. Both shows started around the same time, and I gave both shows around 4 episodes before deciding they weren't funny, and they weren't trending towards funny either. Unfortunate.
Update: Per the anonymous comment posted below, SDSU still lives, probably at least long enough to finish out this season. It's coming back in June at 8:30. Thanks for the info!