During fresh episodes of "Pretty Little Liars," the marketing and publicity teams at ABC Family huddle in a conference room to tweet live with fans.
Cast members and the show's producers also tweet from where and when they can -- and the dialogue often pays off.
Nielsen's Twitter tracking division said "PLL" is the top-tweeted show and ranked No. 1 for the week of June 16-22.
"From a very top level perspective we talk about Twitter being the new water cooler," said Danielle Mullin, the network's vice president of marketing.
While some critics argue the second screen experience of looking at a device while a show is on serves to distract viewers, networks see nothing but an upside.
Some insight into hashtags and TV shows:
HOW HASHTAGS WORK FOR VIEWERS
Hashtags make it easier to filter and search for a topic. Liz Myers, in the TV Partnerships division at Twitter, said viewers "don't have to be mutually following somebody or digging around."
Sometimes hashtags are straightforward with a show's title (#TrueBlood.) Other times they're used as conversation starters and are episode- or scene-specific. (The hashtag #TobyIsBack aired in a recent "PLL" episode when actor Keegan Allen's character returned from an absence.)
Myers said hashtags "can pinpoint moments, drive voting (on a competition series), create content" and offer insight into how to later talk about a show.
ENCOURAGE LIVE VIEWING
If DVRs are helping people watch TV shows at their leisure, live tweeting may provide an incentive to tune in when it counts, in real time.
"The more people who talk about it, the more people watch," said Jenn Deering Davis, co-founder and chief custom officer of Union Metrics, a company that analyzes social media use.
And it could bring in new viewers by "creating impressions for those who aren't already talking about the show to see that conversation and hopefully change the channel," added Myers.
Mullin said she believes tweets can "play into this phenomenon of FOMO -- fear of missing out. When you're on Twitter and your entire feed is people talking about something, if you're not watching you start to feel left out."
Networks try to reward viewers for their tweets. Not only will they retweet fan's tweets from show accounts but sometimes air tweets on screen live, in reruns or during promos.
When it was revealed that Jen Arnold of TLC's "The Little Couple" had cancer, the network selected sentiments from fans with the hashtag #GetWellJen to show later on screen.
More and more actors, like the cast of ABC's "Scandal," are getting into the game and tweeting with fans while a show is airing.
"Back in the day you had to send a self-addressed stamped envelope to get back an 8-by-10 glossy photograph and a sticker (from a celebrity,) Mullin said.
Tweeting about a TV show, and using specific hashtags, is like an immediate focus group.
"We always look and see what people are saying about our shows and it helps us inform our strategy," said Kristen Variola, director of social media for TLC. "We want to give (viewers) what they want. If we see something is really resonating with the fans we like to create more content around that."
Mullin added, "In this day and age it's very hard for any showrunner or writer's room to stay off social media. It's a great way to hear the voice of the people. ... If there's a certain character people don't like or a certain couple people love. (Feedback) is a great tool for storytellers to use when deciding what direction to take their show in."
KEEPS MOMENTUM GOING
Tweeting about a show also keeps people interested for the long haul.
Said Variola: "We are looking at social media as a way to connect with fans year-round, not just when our shows are on the air. With TLC's 'Cake Boss,' we're talking about cakes year round. Not just when you see (its star) Buddy Valastro on the air."
OTHER SOCIAL MEDIA PLATFORMS COUNT, TOO
Twitter isn't the only form of social media engaging TV viewers. ABC Family said during big "tent pole episodes" (like a premiere, finale or special episode) "someone is monitoring Pinterest and live pinning fashion tips, somebody is taking snippets of scenes and putting them up on Tumblr as gifs. Instagram is hugely popular. We have talent taking selfies of themselves while they're live tweeting and they're posting those selfies. ... Fans love it."