The roar rivaled the sound that reverberates around Madison Square Garden when the New York Rangers score a goal.

On Oct. 6, 5,000-plus die-hard fans of AMC’s “The Walking Dead” gathered in the Theater at Madison Square Garden for the New York Comic Con panel that marked the swan song for series star Andrew Lincoln.

The hourlong session included much gushing from fans toward Lincoln for his long tenure on the show as the heroic Rick Grimes, which is set to end during the show’s current ninth season. “Thank you so much for everything you’ve done for us,” said one middle-aged man, earnestly. A young boy dressed up as the character of Rick Grimes’ son Carl was hoisted onto the stage for a hug with his idol.

And then panel moderator Chris Hardwick broke the news that made the floor shake. For their love and loyalty, the fans were to be treated to a screening of the season nine premiere, a full day before it premiered on AMC.

The swooning reaction was an example of how a media company can harness the power of the super fan to build overall goodwill for a franchise. AMC’s “The Walking Dead” has been suffering steep linear ratings declines in its latest live run. But you wouldn’t have predicted that from the fanaticism on display — via cosplay, tattoos and other demonstrations of affection — in the Garden.

“That was a perfect demonstration of one of the transcendent benefits of fandom,” said Susan Kresnicka, a cultural anthropologist and founder of Kresnicka Research and Insights. “It’s a really profound and heightened experience to be in a crowd that has a surge of emotion like that. Those type of moments are what make people wait in line for hours for the chance to a go to a big live event. It produces a really unique and impactful emotional experience of transcendence.”

Media companies can tap into this emotional current by hosting live events, selling merchandise and parceling out extra content.

But there’s an even bigger opportunity in keeping the hard-core base energized to support TV spinoffs and other transmedia storytelling. AMC even created the AMC Premiere subscription service to appeal to fans who want early access to “Walking Dead” episodes without interruption from commercials.

“It starts on television,” says AMC/SundanceTV chief Charlie Collier. “But you’ve got to connect with people where they live — on TV, on the ground, online. We are spending a lot of time trying to better understand what drives our fans.”

AMC shifted “Walking Dead” showrunner Scott Gimple to the role of chief content officer for the franchise last year because there is untapped potential in “Walking Dead”-related content that energizes the fans, Collier said. “We’re in the business of Live-plus-365,” he said. 

As with most everything else in media these days, fandom is greatly enabled by the Internet in general and social media in particular in offering easy means of creating connections between like-minded people across the globe.

“Fandom is just another name for a relationship, like a marriage or a friendship,” Kresnicka says. “We’ve been watching the growing pains of (media outlets) realizing it’s a two-way relationship and learning how to communicate when we have this Internet-enabled paradigm.”

AMC has made investments in studying the habits, hopes and desires of the legion of “Walking Dead” fans as it looks to extend the series into a “multigenerational universe,” per Collier. The response from the cheering in the virtual bleachers has encouraged “Walking Dead” producers to put a bigger spotlight on certain supporting characters, such as Carol Peletier, played by Melissa McBride.

“We realized that there were a lot of people who identified with Carol’s story of having been the victim of domestic violence,” Collier said. “And then she turns into a badass in this terrible landscape where people have to decide who they are going to be when there are no more rules.”

BBC America, a sibling network to AMC, flexed its own fandom muscle the day after “The Walking Dead” panel when it held a New York Comic Con screening event coinciding with the worldwide debut of the new “Doctor Who” season featuring the first-ever female Doctor.

The decision to have star Jodie Whittaker in attendance in New York was an investment in boosting the show’s profile in the U.S. But the moment played around the world as “Doctor Who” devotees were kept abreast of the goings-on with Whittaker at New York Comic Con, thanks to social media.

“There was something special about being able to watch it along with the global community,” said BBC America president Sarah Barnett.

The level of online engagement that BBC America saw for its social feeds of the “Doctor Who” New York Comic Con event predicted the double-digit increase in live ratings for the season premiere compared to previous seasons.

“Before we knew the numbers, we had a sense of the engagement. We knew it was high,” Barnett said. “Our whole approach to the launch was about motivating and activating that fan base and using that excitement to grow the fan base as well.”

(Pictured: “The Walking Dead” star Andrew Lincoln meets a young fan at New York Comic Con)