Houston founder shares how he's using tech to make digital media more effective and equitable

houston innovators podcast episode 173

This month, Mark Walker is celebrating his company's one year anniversary of going public — only the ninth Black-founded business to accomplish this feat on a U.S. stock exchange. Photo courtesy

After working in both sides of the advertising world, Mark Walker thought he could reimagine a platform that would be more efficient and equitable.

Walker co-founded his company, Direct Digital Holdings, an adtech platform, after serving in several roles — from an early hire at Houston digital media startup Questia to business development director at NRG Energy and COO of EBONY Media. He shares on the Houston Innovators Platform how he took this experience in tech, advertising, and media to create his company's platform.

"NRG Energy gave me a top-down view of the value chain, and Ebony gave me a bottoms-up view of the value chain of how media is purchased," Walker says on the show. "At Direct Digital Holdings, we help companies buy and sell media — and we leverage technology to do it. It's really the culmination of both of those experiences."

With over 30,000 publishers on its platform, Direct Digital makes it easier for its core customers — middle market companies looking to buy into the digital media ecosystem — to tap into these opportunities without the tech know-how they might otherwise need. Walker explains that at EBONY, he saw how small to midsize publications — especially the multicultural ones — were being left out on the ad selling side of the equation. The Direct Digital platform bridges the gap on each end.

Founded in 2018 in partnership with Keith Smith, who went through similar professional experiences, Direct Digital went public exactly one year ago after growing the company through strategic M&A activity. Walker says the decision to IPO made the most sense for his company — though it wasn't an easy process. Direct Digital is only the ninth company founded by a Black entrepreneur to go public on a US stock exchange.

"If you think the process is hard — it actually is," Walker says on the journey to IPO. "We were a privately held company, and we knew we had a good growth trajectory and we looked a couple different options. We decided to go public in a very traditional way."

Walker explains there were some risks involved, but the co-founders ultimately decided to shy away from adding in investors who might not have the same ideas for the company's future.

Direct Digital has been a Houston company from the star — despite the city not being home to a booming adtech ecosystem. Instead, Houston — with its collection of Fortune 500 companies and rich diversity — has allowed the business to stand out.

"If you look at and reflect on how our company has been built — from our board of directors to our leadership and management team — we're a majority minority organization all the way across the board," Walker says. "Diversity is very important to us. It's the lifeblood of our business — especially because we're serving publishers in those communities in big way. And moreso, we think you get the best product, thoughts, and ideas from a diverse workforce, and Houston fits right into that mold for us."

Walker shares more about his company's future, advice on IPO, and what all he's watching in adtech — from AI to streaming — on the podcast. Listen to the interview below — or wherever you stream your podcasts — and subscribe for weekly episodes.


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Houston's surge in new startups cools since pandemic peak, study shows

by the numbers

Startup activity in the Houston metro area has dipped since its pandemic peak, according to a new study.

Dating back to 2005, the volume of applications to form new businesses in the Houston area hit its highest level in 2021 (151,804). Since then, though, the application volume has fallen, according to the study, conducted by business debt collection agency The Kaplan Group. Here's the breakdown from the last few years:

  • Applications dropped to 130,011 in 2022
  • Climbed to 145,926 in 2023
  • Dropped again to 138,595 in 2024

Looking at the Houston area’s figures another way, the 2024 total surpassed the 2015-19 average by roughly 60 percent to 90 percent, the study shows.

Dallas-Fort Worth has seen similar startup declines (162,312 in 2021 vs. 153,378 in 2024), but the San Antonio metro area recorded higher application volume in 2023 and 2024 (37,412 and 35,798, respectively) than it did in 2021 (34,208).

The story is different in the Austin metro area. Application volume in 2023 and 2024 (53,200 and 59,190, respectively) exceeded the 2021 total (47,106).

The picture for startup activity in Texas’ four major metros deviates from the nationwide picture.

“America’s real viral trend is entrepreneurship,” says The Kaplan Group. “New business formations are reaching an all-time high across the country.”

In the U.S., per-month business formations soared 435 percent from 2004 (89,561) to 2025 (478,805), the study says.

Amid the growth of startup activity, business bankruptcies in the U.S. have plummeted almost 74 percent since 2004, according to The Kaplan Group.

“The country’s business scene has grown both more resilient and more ambitious in the past two decades,” the collection agency says.

12+ can't-miss Houston business and innovation events for September

where to be

Editor's note: Houston's business and innovation events are back in session. From the return of Houston Energy and Climate Startup Week to a send-off for an impactful innovation leader and several health conferences, here's what not to miss and how to register. Please note: this article may be updated to include additional event listings.

Sept. 5-7 — Houston Hackathon

Impact Hub Houston is bringing back the Houston Hacakthon this month, where developers of all skill sets can work together to propose solutions to some of the Bayou City’s most pressing issues. The event is focused on ideating, designing, and developing both policy-based and tech solutions to improve Houston.

This event starts Saturday, Sept. 5, at noon at the Ion. Register here.

Sept. 8 — Community Celebration: A Send-Off for Paul Cherukuri

Come out to the Ion to celebrate Paul Cherukuri, Rice’s first chief innovation officer, whose visionary leadership has left a lasting impact on Houston’s innovation ecosystem. Cherukuri is leaving the university to accept a position at the University of Virginia. Hear remarks from Cherukuri and enjoy a networking reception following the talk.

This event is Monday, Sept. 8, from 2:30-5:00 p.m. at the Ion. Register here

Sept. 11 — Houston Methodist Leadership Speaker Series – Dr. Evan Collins

The Houston Methodist Tech Hub at the Ion will host its recurring leadership speaker series, this time featuring Dr. Evan Collins, chief of the Houston Methodist Hand & Upper Extremity Center at Houston Methodist and the Houston Methodist Center for Innovation's first innovator-in-residency. Collins will present on the creative process of innovation.

This event is Thursday, Sept. 11, from 4:45-6 p.m. at the Ion. Register here.

Sept. 12 — Future of Space

The Greater Houston Partnership’s 2025 Future of Space event will feature a keynote address by Vanessa E. Wyche, acting associate administrator of NASA. In her new role, Wyche serves as NASA’s chief operating officer, leading more than 18,000 employees and overseeing an annual budget exceeding $25 billion. Discussions will highlight how Houston’s space ecosystem is driving economic growth, technological innovation and new opportunities across the region and the nation.

The event is Friday, Sept. 12, from noon-1:30 p.m. at the Royal Sonesta. Find more information here.

Sept. 15-19 — Houston Energy and Climate Startup Week

Houston Energy and Climate Startup Week returns for its second year, with panels, happy hours and pitch days focused on the energy transition. The week features major events, including the Energytech Nexus Pilotathon, the Rice Alliance Energy Tech Venture Forum, Halliburton Labs Finalists Pitch Day and many others. See a preview of the week on our sister site EnergyCapitalHTX.com and learn more in the event listings below.

This event starts Monday, Sept. 15. The Ion District will host many of the week's events. Find more information here.

Sept. 16 — Energytech Nexus Pilotathon

Grab breakfast and take in keynotes and panels by leaders from New Climate Ventures, V1 Climate, Halliburton, Energy Tech Nexus and many others during Houston Energy & Climate Week. Then hear pitches during the Pilotathon, which targets startups ready to implement pilot projects within six to 12 months.

This event is Tuesday, Sept. 16, from 8 a.m.-5 p.m. at GreenStreet. Get tickets here.

Sept. 16 — Meet the Activate Houston Cohort 2025 Fellows

Meet Activate's latest cohort, which was named this summer, and also learn more about its 2024 group during Houston Energy & Climate Week.

This event is Tuesday, Sept. 16, at 5 p.m. at the Ion. Register here.

Sept. 17 — Green ICU Conference: Sustainability in Health Care for a Healthier Future

Houston Methodist will host its inaugural Green ICU Conference during Houston Energy & Climate Week. The conference is designed to bring together healthcare professionals, industry leaders, policymakers and innovators to explore solutions for building a more sustainable healthcare system.

This event is Wednesday, Sept. 17. from 8 a.m.-3 p.m. at TMC Helix Park. Register here.

Sept. 18 — Rice Alliance Energy Tech Venture Forum

Hear from clean energy startups from nine countries and 19 states at the 22nd annual Energy Tech Venture Forum during Houston Energy & Climate Week. The 12 companies that were named to Class 5 of the Rice Alliance Clean Energy Accelerator will present during Demo Day to wrap up their 10-week program. Apart from pitches, this event will also host keynotes from Arjun Murti, partner of energy macro and policy at Veriten, and Susan Schofer, partner at HAX and chief science officer at SOSV. Panels will focus on corporate innovation and institutional venture capital.

This event is Thursday, Sept. 18, from 7:30 a.m.-5 p.m. at Rice University’s Jones Graduate School of Business. Register here.

Sept. 18 — ACCEL Year 3 Showcase

Celebrate Advancing Climatetech and Clean Energy Leaders Program, or ACCEL, an accelerator program for startups led by BIPOC and other underrepresented founders from Greentown Labs and Browning the Green Space. Two Houston companies and one from Austin are among the eight startups to be named to the 2025 group. Hear startup pitches from the cohort, and from Greentown's Head of Houston, Lawson Gow, CEO Georgina Campbell Flatter and others. This event is part of Houston Energy & Climate Week.

This event is Thursday, Sept. 18, from 5-8 p.m. at Greentown Labs. Get tickets here.

Sept. 19 — Halliburton Labs Finalists Pitch Day

Hear from Halliburton Labs' latest cohort of entrepreneurs during Houston Energy & Climate Week. The incubator aims to advance the companies’ commercialization with support from Halliburton's network, facilities and financing opportunities. Its latest cohort includes one company from Texas.

This event is Friday, Sept. 19, from 8 a.m.-noon at The Ion. Register here.

Sept. 21-25 — AI in Health Conference

The Ken Kennedy Institute at Rice University will present the fourth annual AI in Health Conference, which aims to bridge the gap between artificial intelligence and real-world health outcomes. The event will explore the current landscape of artificial intelligence in health and present a research-driven outlook for the future of computational health innovation.

This conference is from Tuesday, Sept. 23, to Wednesday, Sept. 24. Additional workshops will be offered on Monday, Sept. 22, and Thursday, Sept. 25. The events will be held at the BioScience Research Collaborative at Rice University. Find more information here.

Sept. 25 — Industrial AI Nexus Connect

InnovateEnergy and Industrial AI Nexus will host a talk by Matthew Alberts, manager of innovation and emerging technologies at Southern Company and author of "The Gen AI Manufacturing Revolution: Smarter Factories, Enhanced Products, and Reduced Costs." Alberts will present “The Gen AI Revolution," followed by happy hour and a complimentary book signing.

This event is Thursday, Sept. 25, from 5:30-7:30 p.m. at the Ion. Register here.

Texas is the 4th hardest working state in America, report finds

Ranking It

It's no secret that Texans are hardworking people. To align with the Labor Day holiday, a new WalletHub study asserts that the Lone Star State is one of the five most hardworking states in America for 2025.

The report ranked Texas the fourth most hardworking state this year, indicating that its residents are working harder than ever after the state fell into seventh place in 2024. Texas previously ranked No. 4 in 2019 and 2020, slipped into No. 5 in 2021 and 2022, then continued falling into sixth place in 2023. But now the state is making its way back to the top of the list.

WalletHub's analysts compared all 50 states based on "direct" and "indirect" work factors. The six "direct" work factors included each state's average workweek hours, employment rates, the share of households where no adults work, the share of workers leaving vacation time unused, and other data. The four "indirect" work factors consisted of workers' average commute times, the share of workers with multiple jobs, the annual volunteer hours per resident, and the average leisure time spent per day.

North Dakota landed on top as the most hardworking state in America for 2025 for another year in a row, earning a score of 66.17 points out of a possible 100. For comparison, Texas ranked No. 4 with 57.06 points. Alaska (No. 2), South Dakota (No. 3), and Hawaii (No. 5) round out the top five hardest working states.

Across the study's two main categories, Texas ranked No. 5 in the "direct" work factors ranking, and earned a respectable No. 18 rank for its "indirect" work factors.

Broken down further, Texans have the second-longest average workweek hours in America, and they have the 12th best average commute times. Texans have the 6th lowest amount of average leisure time spent per day, the report also found.

According to the study's findings, many Americans nationwide won't take the chance to not work as hard when presented with the opportunity. A 2024 Sorbet PTO report found 33 percent of Americans' paid time off was left unused in 2023.

"While leaving vacation time on the table may seem strange to some people, there are plenty of reasons why workers choose to do so," the report's author wrote. "Some fear that if they take time off they will look less dedicated to the job than other employees, risking a layoff. Others worry about falling behind on their work or are concerned that the normal workflow will not be able to function without them."

The top 10 hardest working states are:

  • No. 1 – North Dakota
  • No. 2 – Alaska
  • No. 3 – South Dakota
  • No. 4 – Texas
  • No. 5 – Hawaii
  • No. 6 – Virginia
  • No. 7 – New Hampshire
  • No. 8 – Wyoming
  • No. 9 – Maryland
  • No. 10 – Nebraska
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This story originally appeared on CultureMap.com.

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