NBCU made a big move to embrace audience-based buying yesterday, announcing that select advertisers and agencies will be able to use data and automation to buy ads on linear TV. The expansion of the company’s NBCUx platform represents the most significant step by a TV network group yet to adopt a programmatic approach to buying traditional TV ads. NBCU called its initiative “unprecedented.”

I spoke to Aaron Radin, SVP, Partnerships & Portfolio Products at NBCU, who characterized the move as being in response to “clients’ strong interest in buying target audiences in premium video at scale.” Scarcity of premium inventory has been a long-standing challenge in the online video space. By offering audience-based, programmatic buying for linear TV, NBCU is looking to better serve its clients.

Aaron said the expansion into linear is informed by NBCU’s experience using programmatic in online video over the past year. Beyond revealing strong client interest, Aaron said key lessons learned include being thoughtful about how to structure inventory and how to forecast. Aaron stressed that it’s hard to predict where the audience targeting will match inventory so there is no set limit on available inventory which is sourced from all NBCU networks.

That said, NBCU’s programmatic approach in linear has certain safeguards built in that aren’t seen in typical machine-to-machine programmatic video transactions. With NBCU linear, there will still be human intervention to check on inventory availability and potential advertiser exclusivity. For now, only certain DSPs will be able to engage. And this is a private market only, with just NBCU’s best clients able to participate. Finally, NBCU will not be enabling dynamic ad insertion or real-time bidding.

All TV networks are aggressively pursuing data initiatives with enhanced targeting meant to increase the value of ads. As Turner Ad Sales president Donna Speciale said at last December’s SHIFT // Programmatic Video & TV Ad Summit, higher ad value supports Turner’s move to cut ad loads in its linear broadcasts. I asked Aaron if NBCU has a similar game plan but he declined to say.

NBCU’s opening up linear inventory for programmatic buying will almost certainly spur other TV networks to do the same, which means programmatic in linear is poised to gain momentum in 2016. To be sure, its implementation still differs from typical programmatic video approaches, but it signals an important evolution in the market as TV networks work to retain ad dollars in the face of declining linear viewership.

If you’re interested in seeing more of Aaron’s thoughts on programmatic, he participated on a session at last December’s SHIFT event as well. The video is below.