NBCUniversal may make a big investment in digital-media companies BuzzFeed Inc. and Vox Media, according to a report. Pictured: The logo of news website BuzzFeed is seen on a computer screen in Washington. NICHOLAS KAMM/AFP/Getty Images

Comcast’s new 30 Rock sign is not even a month old, but already the Philadelphia cable giant is staking a claim on some of New York’s biggest digital-media brands.

NBCUniversal, which Comcast acquired in 2011, is preparing to make significant investments in BuzzFeed Inc. and Vox Media, according to a report Thursday in the Vox-owned Re/code. The investment in BuzzFeed could be as high as $250 million.

The transactions, which could still fall apart, would value BuzzFeed at $1.5 billion and Vox at $850 million.

The deals had been expected. NBCUniversal, like many traditional media companies, is seeking ways to attract millennial audiences as more young people shun cable and broadcast networks and consume more content online. The social media-focused BuzzFeed Network has a monthly U.S. audience of about 109 million, according to Quantcast, and has been a major force in monetizing online video through “native advertising,” or ads dressed up to look like they’re produced organically on a specific platform. The 9-year-old digital-media juggernaut is expected to generate revenue of $250 million this year, according to Re/code.

Not everyone thinks the viral site is worth the price tag, however. In an article last week, the Wall Street Journal’s Miriam Gottfried wondered whether the digital-media explosion was sustainable, or whether the companies’ business models could adequately monetize audiences amid the growing shift from desktops to mobile. “That is no easy feat given the competing desires of Google and Facebook to extend their mobile-ad dominance,” Gottfried wrote. “Both of these tech giants have been placing particular emphasis on mobile video, which would likely be a focus for Comcast and NBCU.”

A spokeswoman for NBCUniversal declined to comment. A spokesperson for BuzzFeed did not immediately respond to a request for comment.

Last year Fortune magazine reported that BuzzFeed was in talks with the Walt Disney Company, which had considered acquiring the company for $1 billion. But the talks ended after it was determined that the two brands were not a good strategic fit.

There is a great listicle in all this somewhere.

Christopher Zara is a senior writer who covers media and culture. News tips? Email me . Follow me on Twitter @christopherzara .