The Walking Dead scored 16.1 million viewers on its season premiere. That was a ratings record for the show, a record for AMC Networks (AMCX 3.42%), and broke away from Duck Dynasty as cable's story of the year. 

Oh, and it also can now be viewed as the most watched nonsports cable broadcast ever. In 2007, Disney released High School Musical 2, a TV movie which brought in a whopping 17.2 million viewers. High School Musical 2's popularity was high enough that Disney released the next High School Musical in theaters, where it made $253 million at the box office. 

Yet, while Walking Dead scored 16.1 million viewers for its premiere, that number is only for same day viewings. As The Hollywood Reporter noted, looking across longer-term viewership that includes later DVR viewings, The Walking Dead's premiere had 20.2 million viewers in its first three days. Across that same period High School Musical 2 brought in 18.2 million viewers. 

Zac Efron just became the newest victim of AMC's zombie invasion. 

Episode 2 holds in strong

Moving away from the shock and awe of the premiere numbers, the attention now turns to whether Walking Dead can keep its staggeringly large audience throughout the year. 

Early results look good, the second episode of The Walking Dead held in respectably. The episode, which aired on Sunday, had same day viewership of 13.9 million.

That's about a 14% drop-off from the season premiere, which is is a pretty nice performance; last year Walking Dead's viewership declined 12% between its premiere and second episode. As a comparison, when Breaking Bad came back in August its second episode saw ratings fall off 19% from the "premiere" the previous week.

Cautionary cable tales

Looking back at the last season of Walking Dead, viewership last season "bottomed" out around 9.2 million in episode 6. That's just a 15% drop-off from the season premiere. Even better, the show built momentum after a hiatus that lasted between December and February. The season 3 finale was seen by 12.4 million viewers. 

That kind of growth runs in stark contrast to something like Duck Dynasty. Viewership of this season's premiere came in at 11.8 million, significantly higher than last season's 9.6 million. Yet, they show shed viewers throughout the year, eventually seeing its finale last night with 8.4 million viewers. 

That's still an incredible viewing total for cable, but all the same, Ducky Dynasty saw a ratings plummet of 30% from premiere to finale. It's pretty clear the show has hit a ratings high water mark. 

Not exactly Duck Dynasty

Granted, The Walking Dead and Duck Dynasty are different creatures. While both are benefiting from significant buzz, there is little doubt that a concept like Duck Dynasty is far more "faddish."

Walking Dead doesn't need to keep attracting audiences north of 15 million to be considered a success -- it's already in a league of its own at that range -- but it is important that the show keeps delivering at a high quality level. While that's always a given, the show becomes a stronger anchor for AMC Networks with Breaking Bad leaving and Mad Men readying for its last season. 

Plenty of attention has been paid to Walking Dead needing to fill in for Mad Men and Breaking Bad ending their runs, but another area to watch is that AMC is planning a Walking Dead spin-off for 2015. If the company wants another strong property that extends the mania around Walking Dead, the original show will still need to feel fresh before the spin-off arrives. 

It's good to be king

The bottom line is that Walking Dead is a truly remarkable show. As I mentioned in a recent article, it's putting up ratings in the all-important 18-49 demographic that rival Sunday Night Football. That's a show that is commanding $570,000 per 30-second spot this season. 

However, the common trough for many shows is mid-season. Even with relatively strong ratings for episode 2 of the current season, we'll need a few more weeks to see if the audience that found Walking Dead during its last break hangs around.