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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Pharma giant considers Houston for $1B manufacturing campus

in the works

Another pharmaceutical giant is considering Houston’s Generation Park for a manufacturing hub.

According to a recent filing with the Texas Jobs, Energy, Technology and Innovation (JETI) program, Bristol Myers Squibb Co. is considering the northeast Houston management district for a new $1 billion multi-modal pharmaceutical manufacturing campus.

If approved, the campus, known as Project Argonaut, could create 489 jobs in Texas by 2031. Jobs would include operations technicians, engineering roles, administrative and management roles, production specialists, maintenance support, and quality control/assurance. The company predicts annual average wages for these positions to be around $96,000, according to the filing.

The project currently includes the 600,000-square-foot facility, but according to the filing, Bristol Myers Squibb “envisions this site growing in scale and capability well beyond its opening configuration."

The Texas JETI program offers companies temporary school property tax limitations in exchange for major capital investment and job creation. E.R. Squibb & Sons LLC applied for a 10-year tax abatement agreement in the Sheldon Independent School District.

The agreement promises a $ 1 billion investment. Construction would begin in 2027 and wrap in 2029.

“The proposed project reflects [Bristol Myers Squibb Co.’s] enduring commitment to bringing innovative medicines to patients and ensuring the long-term supply reliability they depend on,” the filing says. “The proposed project is purpose-built to support and manufacture medicines spanning multiple therapeutic areas and modalities, positioning the site as a long-term launch and commercial campus for decades to come. These medicines will provide therapies to the [Bristol Myers Squibb Co.’s] patients located in markets both nationally and internationally.”

The Fortune 100 company is considering 16 other cities for the new manufacturing facility in the Central and Eastern markets in the U.S. According to the Houston Chronicle, Bristol Myers Squibb Co is still in the “evaluation process” for its potential manufacturing site.

Last fall, Eli Lilly and Co. selected Generation Park for its $6.5 billion manufacturing plant. More than 300 locations in the U.S. competed for the factory. Read more here.

Houston health tech co. lands NIH grant for AI cancer prediction tool

fresh funding

Houston-based CellChorus and Stanford Medicine were recently awarded a Phase I Small Business Innovation Research grant for the company's AI platform to test how certain cancer patients will respond to therapies.

The funding comes from the National Cancer Institute of the National Institutes of Health. According to a filing, the grant totaled just under $400,000.

CellChorus, which spun out from the University of Houston’s Technology Bridge, has developed TIMING (Time-lapse Imaging Microscopy In Nanowell Grids), which analyzes the behavior of thousands of individual immune cells over time and can identify early indicators of treatment success or failure.

The company will work with Stanford's Dr. David Miklos and Dr. Saurabh Dahiya, who have built the Bone Marrow Transplantation and Cell Therapy Biobank. The biobank manages and stores biological samples from patients treated at their clinic and in clinical trials.

"Predicting which patients will achieve durable responses after CAR-T therapy remains one of the most important challenges in the field,” Miklos said in a news release. “We aim to uncover functional cellular signatures that can guide treatment decisions and improve patient outcomes.”

The project will specifically profile cells from patients with relapsed/refractory large B-cell lymphoma (r/rLBCL). According to CellChorus, only about half of r/rLBCL patients who receive CAR-T therapy "achieve a durable, long-term remission." Others do not respond to therapy or experience relapse.

“The sooner we know whether a cancer therapy is working, the better. To maximize patient benefit, we need technology that can provide a robust and early prediction of response to therapy. The technology needs to be scalable, cost-efficient, and capable of rapid turnaround times,” Rebecca Berdeaux, chief scientific officer of CellChorus, added in the release. “We are excited to work with Drs. David Miklos and Saurabh Dahiya and their colleagues on this very important project.”

CellChorus has previously received SBIR grants from federal agencies, including a $2.5 million award in 2024 from its National Center for Advancing Translational Sciences (NCATS) and a $2.3 million SBIR Fast-Track award from the National Institute of General Medical Sciences in 2023.

Houston museum showcases America's founding documents in rare exhibit

Experience History

As the United States prepares to celebrate its 250th birthday, Houstonians have a chance to see rare documents from the founding of the nation. Freedom Plane National Tour: Documents That Forged a Nation, presented by the National Archives Foundation, will be on display at the Houston Museum of Natural Science through Monday, May 25.

The collection includes a rare engraving of the original Declaration of Independence; official Oaths of Allegiance signed by George Washington, Aaron Burr, and Alexander Hamilton; a draft of the Bill of Rights; the Treaty of Paris, the documented that recognized America's independence from Great Britain; and the tally of votes approving the Constitution.

The National Archives specifically chose Houston as one of only eight cities in the country to host the exhibit as a means to help the documents reach a wider audience outside of the main hub of semiquincentennial events in New England and the Washington, D.C. area.

"One of the things we decided when we put the tour together because we wanted to be off the East Coast," said Patrick Madden, CEO of the National Archives Foundation, who was onsite for the exhibit's opening in Houston. "There's a lot of 250th celebration stuff happening in the original 13 colonies. How do we get it to major markets where larger numbers of people can see it? So in the case of Houston, obviously, [is a] major market in this part of the country, but also we've partnered with the museum twice before with National Archives exhibits, so we knew that they would be up to the task of handling the exhibit and the crowds."

The star of the collection is a rare engraving of the original Declaration of Independence. Secretary of State and future president John Quincy Adams commissioned 200 exact replicas of the document from engraver William J. Stone in 1823. Less than 50 now remain. Madden joyfully pointed out that there are errors in this document, a potent reminder that the men who forged a nation made mistakes.

"There's a couple of typos in it where they had to make corrections," said Madden. "So even the founders, you know, they're all human. That resonates because here these people are making this move against the most powerful nation in the world and putting their lives on the line for a country based on ideas."

Other impressive parts of the collection include official Oaths of Allegiance signed by George Washington, Aaron Burr, and Alexander Hamilton, as well as one of the drafts of the Bill of Rights. Many states would not ratify the Constitution until certain rights were included in the document, leading to Washington going on a national tour assuring state leaders enshrining protections was first on the list. The draft copy on display specifically shows the First Amendment in progress.

Houston is the fourth stop on the exhibition's tour, which will take the documents to Denver, Miami, Dearborn, and Seattle through the summer. Freedom Plane is just one part of a larger patriotic celebration at the HMNS, which includes a film series celebrating American science and culture and general Americana decoration throughout the main hall.

Admission to Freedom Plane is free to the public, but separate from general admission to the museum. Space is limited, and passes are available on a first-come, first-serve basis. Non-members should expect long waits or the possibility that the day's passes are sold out. Only museum members can reserve passes for specific times. Flash photography is prohibited due to the fragile nature of the documents.

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This article originally appeared on CultureMap.com.

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