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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Texas A&M, UH rise in global rankings of universities attracting the most attention

visibility report

Houston and Texas universities had a strong showing on the 2026-27 Global University Visibility (GUV) Rankings compiled by D.C.-based higher ed market research firm American Caldwell.

Texas A&M ranked No. 6 on the list—the top rank of any Texas university. Meanwhile, the University of Houston ranked No. 52, a 15-spot jump from its previous ranking.

The GUV rankings rate colleges that garner the most global attention via news coverage, social media influence, website traffic, YouTube views, and general public interest. GUV evaluated over 1,200 universities across 193 United Nations-recognized countries.

Texas A&M, with its No. 6 global ranking, also claimed the No. 5 spot among U.S. institutions. The university climbed 21 spots from its previous rank.

“News mentions were a driver of Texas A&M’s movement in this year’s rankings, and earned media remains one of the strongest signals of relevance,” Tim Doty, associate vice president for earned media at Texas A&M, said in a news release. “Much of that visibility begins with our faculty and research experts, whose work helps explain, solve and give context to issues people care about. When Texas A&M experts appear in news stories about research, discovery, national security, agriculture, health, engineering, service and the future of Texas, audiences see the university not only as large or well known, but as useful, relevant and necessary to the conversations shaping our state and country.”

In the “Public Interest” category, UH also claimed a top 10 global ranking at No.6. UH touts its overall GUV rankings success to Guggenheim Fellowships, MacArthur “Genius” grants, National Academy membership, studies like researchers breaking the superconductivity temperature record, and success on the football field and basketball courts.

“Across the board, there is no question that the University of Houston is a brand on the rise,” Shawn Lindsey, interim vice president for marketing and communications, said in a news release. “People are seeing our story, hearing about the amazing things happening at UH and actively seeking us out to learn more. We are seeing it in record-high student applications, we are seeing increases in trademark licensing revenue, our faculty are earning global accolades. It’s an exciting time to be a Houston Cougar.”

Other Texas institutions to make the top 250 on the list include:

  • No. 22 The University of Texas at Austin
  • No. 104 University of Texas at Dallas
  • No. 159 Texas Tech University
  • No. 178 Rice University
  • No. 191 University of North Texas
  • No. 248 Texas State University

For the fourth year in a row, Harvard University secured the top spot on the list, followed by MIT, Stanford University and Purdue University. The University of Oxford was the top non-U.S. institution at No. 5.

See the full list here.

Astrodome group seeks new ideas for future of historic Houston landmark

8th Wonder News

The Astrodome may have once been touted as the Eighth Wonder of the World, but its current condition remains one of Houston's most famous follies. In an effort to find a better use for the iconic building, The Astrodome Conservancy has released a Request for Information (RFI), inviting proposals from interested parties on how the historic landmark might be used in the future. Respondents have until September 8 to submit their responses at the official conservancy site.

“This RFI is an opportunity for the market to help shape a shared vision for the Astrodome,” said Beth Wiedower Jackson, executive director of the Astrodome Conservancy, in a release. “We are looking to gather creative, feasible, and financially viable ideas that reflect both the significance of the Astrodome and its potential as a catalyst for future development.”

When the Astrodome opened in 1965, it was a marvel of engineering and the world's first air-conditioned, multi-purpose domed sports stadium. It remained an iconic part of Houston until changing trends in sports sent the Astros and the Houston Livestock Show and Rodeo to newer stadiums with modern amenities. After the 2003 rodeo, the dome was closed, except for a brief use as an evacuation shelter for Hurricane Katrina.

A decades-long fight over what to do with the Astrodome followed that closure. The City of Houston condemned the building for various code violations in 2009. Fully renovating it would cost over $700 million — a tall order for taxpayers. Demolishing it would be far cheaper (around $55 million), but its status on the National Register of Historic Places makes that virtually impossible. Meanwhile, Harris County pays hundreds of thousands of dollars a year to maintain the building.

Proposals for the space have run the gamut. In 2024, the Astrodome Conservancy proposed Vision: Astrodome, which would transform the building into an indoor mall and event space. That still appears to be the foundation of the plan according to the RFI.

The RFI is seeking private investment to partner with the Harris County property. Proposals are merely for planning purposes and will not automatically lead to contracts for development. Section 2.3 states that participants in the new mixed-use space will "require back-of-house infrastructure improvements to support reliable operations at scale," likely meaning that the plan is to fund some of the much-needed renovations via tenants. However, the RFI points out that participants in the revitalized Astrodome will also be eligible for historic space preservation tax credits.

While Vision: Astrodome seems committed to using the stadium as a public space for the entertainment of Houstonians, the RFI is clear other options are on the table.

The Astrodome possibly being used to house a data center is specifically mentioned, though the RFI mandates such a proposal would need to be very upfront about the infrastructure demands and continuing operating costs of such a project. Public backlash against data centers led to Governor Greg Abbott ordering a pause on grid connections to them pending further review.

"The Astrodome presents a unique opportunity for adaptive reuse and redevelopment that honors its legacy while positioning it for long-term community and economic impact," said the conservancy in the release announcing the RFI.

Houston lands $14M in latest CPRIT grants to advance cancer, lab-on-chip research

cancer funding

Thanks to a $4 million grant from the Cancer Prevention and Research Institute of Texas, the University of Houston has recruited a top-tier researcher developing AI-powered lab-on-a-chip technology for early cancer detection.

Tianhong Cui, a professor of mechanical engineering at the University of Minnesota Twin Cities and an adjunct professor of physiology and biomedical engineering at the Mayo Clinic, specializes in microelectromechanical systems and advanced manufacturing at microscale and nanoscale levels. In addition to lab-on-a-chip systems, Cui focuses on biosensors and water sensors.

Lab-on-a-chip devices deliver big results in a tiny package

The CPRIT grant supports Cui’s development of a microscale lab-on-a-chip system for early cancer detection and post-therapy monitoring.

“Lab-on-a-chip technology crams an entire lab’s worth of functions into a tiny device roughly the size of a USB stick,” according to Built In.

Common uses for the technology include medical diagnostics, point-of-care testing, and environmental monitoring.

Lab-on-a-chip work being carried out at UH and elsewhere in Houston promises to revolutionize cancer detection and treatment. For instance, Houston biotech company iBiochips, a spinout from the Houston Methodist Research Institute, makes lab-on-a-chip devices that bolster cancer detection and therapy.

Four local organizations gain $10 million in CPRIT grants

Four other Houston-area organizations received an additional $10 million in grants in CPRIT’s latest round of funding:

  • University of Texas MD Anderson Cancer Center received two $2 million grants to recruit researchers Zheqi Li of Harvard University’s Dana-Farber Cancer Institute and Nikolaos Koundouros of Weill Cornell Medicine.
  • Rice University received one $2 million grant to recruit researcher Maria Akoppyan, formerly of the University of Southern California.
  • UT Medical Branch at Galveston received one $2 million grant to recruit researcher Cristina Santarossa of Johns Hopkins University.
  • Houston-based biopharma company Pulmotect received one $2 million grant to support better outcomes for cancer patients by activating immunity in the lungs as a first line of defense against germs.

The funding was part of $35 million in new CPRIT grants for institutions and companies across Texas approved at the organization's most recent meeting. To date, CPRIT has awarded more than $4.2 billion in grants.

“These awards support research across the cancer continuum from prevention to new classes of therapeutics,” said Dr. Scott Hiebert, chief scientific officer of CPRIT, said in a news release. “The work of these investigators will impact the lives of Texans across the state.”

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