One day last summer Jared Hecht’s fiancée was complaining that she had no good way to coordinate her friends in real time at a Red Rocks music festival. “I called up my friend Steve and said, how do we make this possible?” A week later Hecht, who turned 24 today, and cofounder Steve Martocci, 28, had built a prototype of their group texting service, GroupMe , at a 24-hour hackathon.
Like Twitter  and Foursquare  before it, GroupMe is poised to break out to a broader audience (at least of young geeks) this year's South by Southwest Interactive Festival. “It’s an absolutely perfect use case,” says Hecht. “All these people converging from all over the country, needing tools to plan, speak in real time, and have more fun.” They’re goosing the hype with giveaways  and sweepstakes to enter some of the fest’s parties.
In addition to being cool in itself, the app is sweeping up three big trends in one that you’ll be reading about in lots of Fast Company's SXSW coverage :
1) Device-Agnostic/interoperable. Simultaneously dead simple and feature-packed, GroupMe allows users on dumbphones to stay in one conversation with their Blackberry, Android and iPhone pals, while allowing the app users to achieve location-awareness, then drop down to SMS when the data signal gets overloaded. Other examples: Aviary 's web-based apps.
2) Smaller Social Networking. Sure this app is nice for events, but what about all that time in between? “I do think there is this broader trend out there where people realize they need a platform they can trust to talk with people they actually see and talk to every day,” says Hecht. Examples; Path , Facebook Groups.
3) Post-Groupon Social Marketing. Hecht and Martocci actually got a paying ad to run on their very first prototype--"I see you and your friends are looking for a place to watch the Lost finale, would you all like a half-off coupon to the Brooklyn Bowl?" Hecht describes their business model as "a realtime Groupon or Adwords." Examples: Everything in this article .
(Catch our own Ellen McGirt's chat with Hecht and Martocci on Sunday March 13 at 10:30am on the Pepsico stage, or right here on FastCompany.com/sxsw-2011 )