What determines the longevity of a television show? Is it simply down to views, or is it the message conveyed from episode to episode that also makes a difference? What does that message have to be in order to lead to long-term success?

For South Park, the creators’ ability to make light of current events has been so successful, the show just finished its 19th season Wednesday, with a 20th season confirmed in 2015. Although having drawn plenty of critics for the manner in how it’s parodied certain topics and celebrities, Trey Parker and Matt Stone have continued to entertain much of the country with their brand of humor.

In earlier seasons, the two were able to accomplish despite not having continuity from episode to episode. As the years progressed, the show slowly started to gain continuity, not always for an entire season, but in three-episode storylines. One example came at the end of 2013, when South Park put together a mini-series that parodied Black Friday shoppers’ activities, HBO’s Game of Thrones, and the “battle” that year between Playstation 4 and Xbox One as the top video game console.

2015 saw the show’s 19th season follow recurring themes throughout all 10 episodes. Topics included the controversies involving political correctness, gentrification, gun control, and body shaming, among others. The fact that South Park is able to explore these topics over an entire season is partially due to the fact that Stone and Parker have recently changed the show’s structure to one 10-episode block in the fall, as opposed to two seven-episode blocks in the spring and fall. This allowed viewers to keep up with the plot lines easier – instead of waiting several months for the season to continue – especially since the show’s website now only posts certain episodes for free at a time.

Season 19 ended Wednesday on a mini-cliffhanger, with “PC Principal,” introduced at the beginning of the season, announcing that he’ll stay in the town and help it continue to become more politically correct. Will this continuity be seen in 2016, or will the creators decide to take the show in a different direction? The mantra for upcoming seasons has often been to “expect the unexpected,” and that doesn’t seem to change soon.