Most Mondays, Jacob Geiser watches TNT's pro wrestling with buddies who are so tight they finish each other's wisecracks. But when he sinks into the couch in his Eden Prairie apartment to enjoy the action on his 50-inch plasma screen, there's no one else in the room.

In fact, he's never even met most of his wrestling friends.

Geiser, 24, is part of a rapidly growing, potentially influential group that keeps one eye on the TV and the other on a laptop or smartphone, tweeting furiously with cyberpals about everything from an outrageous chokehold to an OMG twist on ABC's "Nashville."

"I like the idea that there are other people watching the same thing I am and that I can engage with them," said Geiser, a desktop support specialist who once spit out 250 tweets during an episode of "Lost." "There are shows I can't talk to my wife about because she's not that into them, but I can converse through social media for three or four hours."

In just a couple of years, the marriage between social media and TV watching has gone from a curious novelty to an addictive habit, one that is changing how we watch television and, perhaps, what we watch on television.

This year Americans have posted more than 750 million social-media messages on such sites as Twitter and Facebook while watching their favorite shows, according to Trendrr, a New York-based company that tracks social media. Traffic is up more than 800 percent from a year ago.

Geiser admits he misses some of the story lines while his fingers are flying across the keyboard.

"Often you can just listen to the audio and still follow what's going on," he said. "But there are definitely moments in, say, 'The Walking Dead,' where you want to look up, pay attention and watch them blow up a herd of zombies."

Talking with the stars

Those moments can seem even more explosive when an insider from the show tweets back.

Almost the entire cast of ABC Family's "Pretty Little Liars" has answered fan questions during episodes. That may explain why the show's midseason finale in August drew 709,000 tweets in an hour, making it the most "social" TV episode in history.

"Back when I was a teenager, the only way you could express interest was to send a letter to Shaun Cassidy and then wait six weeks for something to come in the mail," said Danielle Mullin, ABC Family's vice president of marketing. "Now you can directly tweet one of our stars and if they tweet back to you, it's like the best day of your life."

Not all stars are eager to spend their evenings swapping messages with fans. Dana Delany, star of ABC's "Body of Proof," was reluctant to get a Twitter account. But last year the network put the pressure on. Now she's hooked.

"Viewers can get little inside stories about shooting an episode, from what I was wearing to how did I learn to cry like that," Delany said. "You can meet people all over the world and have direct conversations with people who share similar interests."

Kunal Nayyar, who appears on CBS's "The Big Bang Theory," also live-tweets, but while he thinks it can help humanize a celebrity, "you also run the risk of losing the magic."

That was CBS's concern four years ago when "Survivor" host Jeff Probst announced that he planned to tweet during an episode. Executives worried that Probst would shatter the illusion he was broadcasting live from a remote island.

Several fans tweeted back, saying that while they used to tape the show for later viewing, they would begin tuning in live to "watch" with Probst.

Advertisers love it when viewers find a reason to watch live, eliminating the option of fast-forwarding through commercials. Two weeks later, CBS promoted a "tweet week" for all its prime-time shows.

"You can sit on the pot and say you don't like it [Twitter], and it'll walk right by you," Probst said.

Media executives are also looking at ways they can reach ultra-loyal fans through social-media campaigns. "Pretty Little Liars" features a mysterious character known only as "A." Viewers -- primarily girls and young women -- turned it into a social-media "meme," posting photos of the letter showing up in a piece of toast or as twigs outside a bedroom window.

ABC Family quickly capitalized on the viral trend, creating a photo contest with the winner getting to visit the show's set.

Networks wave a caution flag

Just how far TV will take this burgeoning relationship remains to be seen.

Trendrr CEO Mark Ghuneim believes Showtime, for example, is monitoring social-media responses to "Homeland" to evaluate whether plot twists are coming too quickly. He also thinks viewers will increasingly tailor their own viewing habits to have a shared experience.

At the same time, TV programmers need to be cautious about putting too much weight on social-media reaction, said ABC Entertainment president Paul Lee. "You do get a sense of what's resonating and what's controversial," he said, "but it's more of a reflection of passion from a small group of people."

ABC's "666 Park Avenue" was among the most-tweeted new programs this fall and it's already been canceled.

But don't tell Michelle Dye of Eden Prairie that the marriage of TV and social media isn't important.

"This is how people are going to watch TV from here on out," Dye said.

She jumped on the bandwagon a little less than a year ago, checking out her Twitter account during Travel Channel's "Ghost Adventures" and the state hockey tournament.

"In the olden days, you'd go in to work the next day and talk about what you saw, but now you can get instant gratification," said Dye, who works in a school cafeteria. "It makes the experience interactive for me and a lot more fun."

But her habits can send conflicting messages to her three children. Two years ago, she gently admonished her youngest son for playing a hand-held Nintendo game while sitting in front of the TV.

"One or the other," she told him.

Recently her son, now 11, caught Dye watching TV while looking at her laptop.

"One or the other, Mom," he said. "One or the other."

Neal Justin • 612-673-7431 • @nealjustin