The sun is about to rise on a third season of “@Summerbreak,” the AT&T-sponsored program designed to play out on nearly every screen possible – except on a TV set in traditional fashion.

The series’ new season, which follows a group of real high-schoolers enjoying their last summer before embarking on the road to higher education or adulthood, is slated to debut this Sunday, June 21, and its backers are expanding the venues upon which the program can be seen. “@Summerbreak” has always been distributed via Facebook, Twitter, Tumblr and Instagram, and its backers have stretched out to Snapchat and Vine. In 2015, some content related to the series will be available via Periscope, the live video-streaming app owned by Twitter, as well as We Heart It, a social-network based on images that users can collect and share, said Billy Parks, a co-creator of the series who is a senior vice president of FullScreen Strategic Content Studio.

“We learn more about what works” after each new season, Parks said in an interview. “We are able to drive the narrative” with new types of social media, “and the platforms we are using drive the way we tell the story.”

Between the various social-media outlets belonging to “@Summerbreak” and the kids who have played a role in the show, the content has notched 917,065 followers across YouTube, Vine, Instagram, Tumblr and Twitter, according to the producers.

“@SummerBreak” is, at its heart, an ongoing experiment by a group of media entrepreneurs to determine whether video content distributed via new-tech makes enough of an impression to be worthwhile for both an audience and advertisers. The series tends to follow nine teens (plus, in this season three members of the second season), who just graduated from high school in the midst of one last hurrah.

Rather than being told in 30- or 60-minute increments on TV, however, the show is told via posts on Twitter in feeds belonging to the show and its teen protagonists, as well as through posts, videos and more. The series is produced by the Chernin Group, along with FullScreen and Astronauts Wanted.

AT&T has backed the series since its inception, with an eye toward using the production to tell fans of the show about new services and devices available from the telecommunications giant. The key, said Liz Nixon, director of engagement marketing for AT&T, is to find ways to augment the experience of consuming the show.

To be sure, AT&T posts promotional messages in venues where content from the program is available, and places devices in the stars’ hands during filming. But, said Nixon, the company tries to do so in a way that helps the teens get things done or enhance the connection viewers might have with the program. “The cast will be outfitted with the latest devices, and that is a very natural behavior for them to have their phones with them as they spend the summer together and document their experience and stay in touch with each other,” she said.

When the company found in a previous season that some of the kids were interested in making a music video, it made sure some of its equipment was offered to them to help in their quest. In the first season, AT&T rushed out waterproof devices to kids when executives found a group planned to go for a swim at a local quarry. AT&T also organizes meet-ups with the kids from the show, both in its stores and in online venues, Nixon said.

Where big TV networks like CBS and NBC ready elaborate promotional campaigns to launch a new program or a new season of a series, the backers of “@SummerBreak” say they need only ramp up activity on the show’s social-media feeds to gather the faithful. Indeed, the producers have not made a formal announcement about the third-season launch date until today, Parks said.

Part of the appeal, he said, is that the series is always on, and discoverable by people who have not watched it before. “We can get new members in,” said Parks, because viewers realize they can watch the first episode from the start or catch up even if the season is half-done. “We had more viewers on season-one content during the season-two @Summerbreak than we did in season one,” he said.