Known for his founding roles at both Twitter and the credit card interface Square, Jack Dorsey has quickly moved into a rarefied realm of St. Louis-bred celebrities, expats who maintain a popular and respected presence in town. Though his time is now largely spent away from the city, he continues to draw large, enthusiastic audiences with each returning visit.

On Thursday evening, he brought the Square-backed “Let’s Talk” discussion series to St. Louis, where a sold-out crowd greeted him and four panelists, all of whom who work within blocks of the hosting venue, the Casa Loma Ballroom.

As the lights dimmed inside the historic concert hall, the ballroom lit up a bit from the ground floor, as dozen of smart phones and tablets popped out of pockets. Throughout the duration of the Q-and-A guided by Dorsey, attendees posted live updates and opinions about what was happening onstage, while beats from the Artopia street festival outside seeped through the venue’s vast second-floor windows.

The proceedings focused on real-life stories of the four panelists: Jewelry artisan Katie Miller of Scarlett Garnet, Pete Wissinger of Whisk: A Sustainable Bakeshop, Cherokee Street Bikes founder Jeremy Schwartz, and Sump Coffee’s outspoken co-owner Scott Carey. The first three businesses are found on Cherokee Street, the blossoming South St. Louis magnet that calls the Casa Loma home. Sump is located just a few blocks away.

“You wouldn’t have seen this two years ago on Cherokee,” Jason Deem, a resident, business owner and landlord on Cherokee, said prior to the event. “These are great selections, a good panel. It’s a group very representative of small-business owners in St. Louis.” He spoke of the corridor’s rise, much-documented within St. Louis as an urban success story.

Dorsey asked most of the questions and sought, early on, to distance the conversation from an event solely intended to promote Square, even as attendees passed by a series of Square offerings on their way into the hall. Mayor Francis Slay, perhaps noting the techie audience, took off his tie and rolled up his sleeves as he introduced the evening, giving a special nod to Dorsey while alluding to the idea that the next big Internet success story might be found in the room. And while the mayor’s civic boost gave the crowd an early reason to cheer, things got interesting about halfway through the presentation, when Carey opened up on his feelings about city bureaucracy.

After an interesting but relatively tame conversation about each business owner’s goals, starts, obstacles and successes, Carey’s impassioned address was a call to arms for the city to both relieve burdens on new business owners and provide better customer service to those launching businesses. Clearly turning after Carey’s broadside, the night ended with a degree of constructive criticism, one that had Slay’s official Twitter feed stating shortly after the event, “A lesson from #letstalk: city government must do better than it has in the past. #fgs.”

Cherokee Street in May 2011. Credit: Paul Sableman on Flickr

Carey, a former attorney, did cite STL’s positives as well. “When you throw a rock into the pond here, you can see the ripples,” he said. “When you throw a rock into a pond in a city like New York, you see nothing.” For a growing group in St. Louis, Cherokee Street has been the place to make those ripples.

Though Cherokee serves as a beacon for local cool, the audience and panel reflected the reality of its last decade: A big bubble of mostly white, thirtysomething creatives who generate much of the heat and buzz. To its credit, though, the neighborhood’s new (and some old) residents have been as resilient as they are monochromatic. Less than three months back, the block suffered a workplace murder/suicide that left four dead.

But it seems that business on Cherokee has changed for good. The street’s response was swift. “There’s so much energy and push behind these small businesses,” Miller said while walking into a newly reborn bar nearby called Fortune Teller. “I think the overall message was that you’ll do well if you’re passionate and you stay true to yourself.”

Even as Dorsey was quick to distance Square’s central role in the evening, a moment between the Casa Loma and Fortune Teller illustrated that his own side venture is gaining traction. A food truck at Artopia, the popular Seoul Taco, was selling its amalgam of Korean and Mexican street foods. The credit card interface it used? It was Square.