This week Ryan Murphy's horror anthology American Horror Story wrapped up its third installment with the conclusion of its "Coven" storyline. The drama, which debuted in 2011, has always played by its own rules and each year seems to find a new way to one up itself in shock value. As a result, though, it's always come with a question mark: will audiences respond to it in a positive way? Well, so far so good and it is having a profound effect on the industry.

"American Horror Story: Coven" (Credit: FX)

Game change

FX (a subsidiary of News Corp (NWS -0.11%)), knew it was a risk to air this show. The network helped give series creator Ryan Murphy his big break with Nip/Tuck and knew how dark the talented showrunner could get with his material. Yet it was a groundbreaking concept -- how could a network that has "there is no box" as a motto not take a flier on the project?

The idea was simple in that it would be a different self-contained story every year with an "A-list" cast bringing it to life (or death, as the case often has been). With Dylan McDermott, Connie Britton, and the incomparable Jessica Lange attached for the first round, FX's decision was looking better with each passing day.

Eventually it not only proved to be a ratings hit, but FX saw a secondary boost in that it was suddenly back in the awards game. While the network has always had stellar programming, it wasn't always recognized. Now Horror was a putting a real fright into category leader HBO.

Because it was a self-contained story, it was eligible for the newly merged "Made For TV/Mini-Series" category at the Emmys, which caused a huge industry stir. Other networks questioned the legality of the entry, but the Academy of Television Arts & Sciences made the right call and the show has earned 17 nominations, with a handful of wins.

"American Horror Story: Murder House" (Credit: FX)

Ratings smash

From the beginning, viewers embraced the unique concept and season one, nicknamed Murder House, averaged around 2.8 million viewers an episode. Yes, the series took a small hit the following year as Asylum fell a bit and netted 2.5 million viewers an episode, but they returned in droves for Coven.

The third mini-series in the Horror anthology is expected to end its run with an average viewership of 4 million. This week's capper snared 4.2 million viewers to be exact and 2.8 million of those fell in the all-important 18-49 demographic advertisers' love. When all is said and done, the episode could be the highest performer yet for the drama.

FX was also quick to note that the mini-series was in the top 20 in the 18-49 demo overall and number five overall when looking just at cable (behind The Walking Dead, Breaking Bad, and network sibling Sons of Anarchy).

"American Horror Story: Asylum" (Credit: FX)

The Horror business

American Horror Story's success comes at a good time for FX. The network is preparing to say goodbye to Sons later this year and Justified in 2015. At that point it will be FX's most established series and an anchor show that, along with The Americans and The Bridge, will need to help the network continue hold its footing until some of its newer series gain traction with audiences.

Yet the majority of Horror's success rests with its cast. The show can get actors like Lange, James Cromwell, Kathy Bates, and Angela Bassett because the show is self-contained. The network can lure these big-name film stars to TV because it is appealing to them that it is such a small time commitment and the upside is huge.

FX has literally helped changed the business model and rivals like HBO are beginning to take notice. The network took a page out of FX's playbook and this year launched True Detective. The (mini)-series is also designed to be an anthology and, as a result, was able to attract Matthew McConaughey and Woody Harrelson for the lead roles. It won't be long until other networks update their strategy as well.

Overall, this is a franchise that's proven that short-form series have just as much of a role on TV as long-form and the business impact has already been considerable. The Emmys are now considering separating the "Made-for-TV Movie/Mini-Series" category back into two separate races. This comes after they were unified because the "mini-series" field was seeing fewer and fewer entries.

With the new awards category and the commercial and critical success of American Horror Story, it's likely we'll see the medium continue to evolve. Competitors who don't follow FX's lead might miss out on name actors and Emmys, and could even see a decline in their ad values. Now that would be scary.