'Pretty Little Liars' cast prepares to tweet goodbye

LOS ANGELES – What's the most impactful show of the past decade? If you said "American Idol" or "Game of Thrones," you're probably well over the age of 35 and use social media primarily to show off photos from your weekend in Branson.

All the cool kids know the correct answer is "Pretty Little Liars" — and they've got the numbers to back it up. They're just not the numbers older folks are used to.

"PLL," in which five teenage girls are terrorized by a mysterious villain after the disappearance of their classmate, was a hit by conventional standards, from its premiere in 2010 to the final season that concludes Tuesday with a two-hour finale, followed by an hour of the cast and creators patting themselves on the back. The soap consistently finished near the top of the Nielsen ratings among females 12 to 34 and was the most watched series on ABC Family, now known as Freeform.

But the show's legacy truly emerges through a relatively new measurement — social media influence. By that yardstick, "PLL" is the most powerful series on TV, more than doubling the number who weigh in on "The Walking Dead."

"It has a lot of unique elements that set it up for success in the social media space: an ongoing mystery, plot twists and turns, cliffhangers and what we call OMG moments," Danielle Mullin told USA Today back in 2013 when she was the network's marketing vice president.

"PLL" remains the most tweeted-about show on television, generating more online comments per episode than the more ballyhooed "Grey's Anatomy," "Empire" or "The Rachel Maddow Show."

"It wasn't really intentional," said series star Lucy Hale, who last year was the 42nd most followed person on Instagram. "It was like social media got big right after the show started. I think we were the first show that included hashtags and really interacted with fans."

"I enjoyed it, I think, just as much as they did, getting to hear their theories and their thoughts about what might be coming up," said actress Shay Mitchell, who admits she didn't even know what Twitter was when the show got picked up.

Input from rabid fans even infiltrated the writers' room.

"I'd say if you see an overwhelming trend on Twitter — if there is a couple that people really love or a couple that people really don't love — we've taken that into account as we move the story forward," King said.

Being accessible to viewers sometimes comes at a price. The show came under fire in 2015 when it revealed that the baddie who was tormenting the quintet was transgender. That didn't sit well with people who had praised the series for its inclusive nature. In its seven seasons, "PLL" never earned a single Emmy nod, but the Gay and Lesbian Alliance Against Defamation (GLAAD), which bestows media awards annually, nominated it five times in a row as best dramatic series, a streak that ended after the revelation.

"Creatively, we still stand by our choice, but you don't want anybody to feel bad about watching the show in any way, shape or form," King said.

King has been exploring the price of fame in a social media world in her new Freeform series, "Famous in Love," in which Bella Thorne plays an overnight sensation in Hollywood who can't seem to buy a cup of coffee without her order going viral.

"Everybody will try and change you in this business, make you different with social media," said Thorne, whose sexual orientation became a trending item in 2016. "People will try and tear you down and make you look like something you're not, so you have to really remain who you are."

But don't expect the actors of young Hollywood to melt down their cellphones anytime soon. Thorne's openness with fans helped earn her a Teen Choice Awards nomination last week as TV's best dramatic actress.