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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UTHealth Houston team joins NASA initiative to protect border drinking water

water watch

Climate change means far more to public health than living with hotter days. Transformations in our weather are contributing to challenges in accessing safe drinking water in some communities.

One of the most dire situations is along the US–Mexico border. The National Aeronautics and Space Administration (NASA) is seeking to address that issue with its Water Quality Applications program. An 11-researcher project led by a UTHealth Houston School of Public Health faculty member has been selected to participate.

“Drinking water is one of the most fundamental public health protections, but producing safe drinking water involves a delicate balance,” Yun Hang, assistant professor of environmental and occupational health sciences, said in a news release. Her team’s proposal was one of 93 that were submitted for funding through NASA’s Research Opportunities in Space and Earth Sciences (ROSES)-2025 program.

This is the first time that NASA has worked with a team devoted to water quality applications. The group, which includes researchers from across the nation, will use satellite observations of Earth, as well as hydrologic modeling, to potentially anticipate and act on water quality conditions as they change. Challenges addressed over the course of the three-year program, which kicked off in June, might include problems with water quality due to climate variability and increased pressure on water resources.

Hang’s team will focus on a pair of borderlands: Paso del Norte and the Rio Grande Valley.

“Working closely with El Paso Water ensures that our research addresses real operational needs while helping utilities better prepare for climate-related water quality changes and continue providing safe drinking water to communities across the Texas border region,” Hang added in the release.

She and the team will use data gathered by NASA on both past and future Earth-observing missions, which will allow them to track environmental changes that may affect source water quality. Combined with past water treatment records and hydrologic models, the team will also utilize artificial intelligence to develop predictive tools that aim to stop issues before they become larger hurdles to water safety.

Another one of the project’s goals is to create visualization tools and source water summaries that can be utilized by those without scientific expertise. The tools will be produced in English and Spanish to further broaden their accessibility.

The hope is that the materials made by the team will also go far beyond the border, with protocols that can be adapted or adopted by other areas dealing with water quality issues.

U.S. News declares Houston hospital No. 1 in Texas for the 15th year

Top of the Chart

Houston Methodist Hospital and over a dozen more Houston-area hospitals have earned bragging rights in U.S. News & World Report's newly released rankings of the Best Hospitals for 2026-2027.

Every year, U.S. News annually evaluates nearly 4,500 U.S. hospitals to determine which meet the publication's rigorous standards and offer the best care for patients across 14 adult specialties and 23 procedures and conditions. New to this year's batch of rankings, U.S. News introduced regional rankings in cancer; cardiology; heart and vascular surgery; orthopedics; and rehabilitation.

Houston Methodist Hospital was the only Texas institution named on U.S. News' Best Hospitals Honor Roll, a prestigious list of the 20 best medical centers in the country. Houston Methodist also reigns as Texas' best hospital for the 15th consecutive year.

The hospital also shines among the nation’s best in 10 specialties:

  • No. 5 – Gastroenterology and GI Surgery
  • No. 7 – Obstetrics and Gynecology
  • No. 10 – Cardiology, Heart, and Vascular Surgery
  • No. 11 – Pulmonology and Lung Surgery
  • No. 13 – Neurology and Neurosurgery
  • No. 19 – Cancer
  • No. 21 – Orthopedics
  • No. 23 – Diabetes and Endocrinology
  • No. 24 – Geriatrics
  • No. 43 – Urology
Houston Methodist also earned high performing distinctions across one regional specialty (Rehabilitation) and 21 procedures and conditions.

"This recognition reflects the remarkable dedication of our physicians and employees and their tireless focus on delivering unparalleled care to our patients," said Houston Methodist president and CEO Marc L. Boom, M.D. in a press release. "While we are honored by this recognition, its true significance lies in what it represents — an unwavering commitment to putting patients first."

Elsewhere in Houston, The University of Texas MD Anderson Cancer Center ranked as the No. 1 best cancer hospital in the nation for the 12th year in a row.

"This ranking is a tremendous honor, and it reflects our unwavering commitment to continue making progress in our mission to end cancer," said UT MD Anderson president Peter WT Pisters, M.D. "We are deeply grateful to everyone who made this recognition possible: our faculty and staff, volunteers, donors, and the patients and families we are honored to serve."

MD Anderson also earned national rankings in two specialties — Urology (No. 6) and Gastroenterology and GI Surgery (No. 16) — and it received high performing distinctions in six procedures and conditions: Colon Cancer Surgery; Ear, Nose, and Throat Surgery; Gynecological Cancer Surgery; Leukemia, Lymphoma, and Myeloma Treatment; Lung Cancer Surgery; and Prostate Cancer Surgery.

The additional Houston hospitals that ranked among the best in Texas for 2026-2027 are:

  • No. 3 – Houston Methodist Sugar Land Hospital (tied with Baylor University Medical Center Dallas)
  • No. 5 – Baylor St. Luke's Medical Center, Houston
  • No. 6 – Memorial Hermann Hospital, Houston
  • No. 7 – Houston Methodist The Woodlands Hospital
  • No. 10 – Memorial Hermann Greater Heights Hospital (tied with St. David's Medical Center, Austin)
  • No. 14 – Houston Methodist Baytown Hospital
  • No. 15 – Memorial Hermann Memorial City Medical Center, Houston
  • No. 21 – Houston Methodist Clear Lake Hospital, Nassau Bay; St. Luke's Health-The Woodlands Hospital; University of Texas Medical Branch, Galveston (also tied with six more Texas hospitals)
  • No. 30 – Memorial Hermann Sugar Land Hospital (tied with five other Texas hospitals)
  • No. 36 – HCA Houston Healthcare Kingwood (tied with Parkland Health-Dallas)
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This article originally appeared on CultureMap.com.

Houston helps power Texas’ rise as AI infrastructure hub, new report finds

eyes on ai

Houston plays a major role in Texas’ rapidly evolving AI economy, a new report indicates.

The report from Build American AI, a pro-AI advocacy group, notes Houston’s growing AI presence includes:

  • A factory being built by AI chipmaker NVIDIA and electronics manufacturer Foxconn that will produce AI supercomputers and infrastructure systems
  • Houston Methodist’s use of ambient AI to listen to health care providers’ conversations with patients, eliminating the need for manual notetaking
  • An abundance of AI products and services for the energy sector

Across the state, billions of dollars in new AI investments are fueling advancements in construction, manufacturing, energy production, logistics, and health care, according to the report.

“Texas is not merely a place where AI products will be used. Texas is becoming one of the places where the AI economy is being assembled,” the report says.

Particularly noteworthy are four major AI-related projects around the state representing an investment of more than $140 billion, including Google’s $40 billion buildout of AI data centers.

“While California had a headstart in building the software era, Texas will build the infrastructure era,” says the report. “That is not a slogan. Economic research has revealed for decades that innovation happens where the local conditions make building and collaboration possible, and Texas is positioned to be a central hub.”

According to the report, components of Texas’ infrastructure era include:

  • Energy leadership
  • Top-tier hospitals
  • Semiconductor investments
  • Construction capabilities
  • Data center growth
  • Major companies and universities

On the workforce front, Stanford University’s 2026 AI Index found Texas had 80,547 AI job postings in 2025, accounting for 8 percent of the national total.

“Texas no longer needs to ask whether AI will reshape the economy. It already has,” the report concludes. “The question is whether Texas will merely host part of that future or lead it.”

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