The most visible reversal came with the effective end of the Privacy Sandbox experiment and Google’s decision to walk back plans to fully deprecate third-party cookies in Chrome.

After years of insisting that Privacy Sandbox represented the future of web advertising, Google instead opted for optionality, underscoring a long goodbye to a project that never won broad industry trust. For many ad tech companies, the shift confirmed that the economics of the open web proved harder to re-engineer than anticipated.

That disappointment was partly offset by rapid progress in AI. Gemini emerged as the connective tissue across Google’s ad stack, touching everything from creative generation to bidding and optimization. Tools such as AI Max underscored how aggressively Google is embedding generative AI into performance advertising, even as buyers began scrutinizing the trade-offs around control and transparency when evaluating Google’s AI Max.

Meanwhile, YouTube became one of Google’s clearest commercial bright spots. As linear TV continued its structural decline, YouTube increasingly established itself as the default television platform in the living room. That shift was not just about audience share.

The company leaned into TV-style selling, moving beyond the language of pre-roll and toward guarantees, reach and upfront-style commitments, reflecting how YouTube has been talking TV — and now it’s selling that way.

Together, AI momentum and YouTube’s dominance, and federal judges’ lack of conviction, helped cushion a bruising year on the regulatory front, as Google absorbed successive antitrust losses without materially altering its commercial trajectory.

Amazon’s DSP push gathered pace

If Google’s year was defined by adjustment, Amazon’s was defined by acceleration.

Despite executing one of the largest headcount reductions in its history, Amazon continued to pour investment into advertising infrastructure — particularly its demand-side platform.

Advertisers’ desire to connect media spend directly to transactions only intensified, reinforcing Amazon’s advantage at the point of purchase. That dynamic helped fuel rapid growth in Amazon’s DSP even as the company tightened costs elsewhere.

Internally, the strategy was framed as doing more with less. Automation and AI became central to maintaining momentum with a leaner workforce, shaping how Amazon aims to do more with less across its ad business. The ambition was clear: turn a $17 billion quarterly ad haul into sustained DSP expansion, laying the groundwork for a much bigger push heading into 2026.

That momentum did not come without casualties.

Much of Amazon DSP’s growth came at the expense of independent ad tech, with The Trade Desk emerging as the clearest counterpoint. Once positioned as the standard-bearer for open-internet buying, the company spent much of 2025 responding to buyer pressure on pricing and flexibility, culminating in a decision to loosen its grip on pricing.

Leadership at The Trade Desk may ultimately view 2025 as an annus horribilis — a year defined less by category leadership than by defensive repositioning as Amazon redrew the competitive map.

Even so, unease accompanied Amazon’s ascent. As its DSP gained share, questions around concentration, data use and neutrality grew louder, exposing the trust fault line running through Amazon’s ad ambitions.

By year’s end, the direction of travel was unmistakable: advertisers’ spend was concentrating in platforms (already) with significant market share, a sign that ad tech is now increasingly shaped by the pull of scale.

Numbers to know

• Google’s Paul Gubbins posted a LinkedIn poll, posting the question: “If one programmatic buying model is to fade away within 24 months, what would it be?” 
• 39% Private marketplace deals
• 31%: Preferred deal
• 10%: Openmarket programmatic
• 20%: Programmatic guaranteed 

What we’ve covered

Programmatic agency execs speak out on CTV transparency

“There’s been a lot of AI slop out there lately. We’re seeing a lot of it on YouTube, especially… we’re seeing 5% of [ads running] on AI slop… it’s growing like crazy right now.”

Pitch deck: How Amazon is recasting Twitch as a core part of its CTV pitch

Amazon is positioning Twitch as a defining asset in its CTV ambitions, folding the platform’s hard-to-reach audience and live-video inventory into the same pitch it uses to sell Prime Video and Fire TV. 

What we’ve heard

“The ‘TV’ wars are effectively over, and YouTube won. It is now the single biggest channel on television screens in America.” 

— “Media cartographer” Evan Shapiro, notes how YouTube was the big winner in 2025’s TV wars – even if ad execs are seeing some concerning trends as indicated above.   

What we’re reading

OpenAI hires an executive from Google to lead M&A

OpenAI is hiring Albert Lee, a long-time corporate development executive at Google, as head of corporate development, according to people with knowledge of his move, reports The Information’s Valida Pau. 

Doxers posing as cops are tricking Big Tech firms into sharing people’s private data

The hackers typically use one of two ways to trick companies into making them believe the emails are coming from real law enforcement agencies. 

Meta tolerates rampant ad fraud from China to safeguard billions in revenue

A Reuters investigation reveals the owner of Facebook, Instagram and WhatsApp decided to accept high levels of fraudulent advertisements from China. Internal company documents show Meta wanted to minimize “revenue impact” caused by cracking down on the scams.

Sushi, Sashimi and the state of supply quality

Viant’s Keith Petri argues that Intermediaries know identity drives demand, so they inject it where it didn’t exist upstream. Without precision or verifiable provenance, this becomes identity garnish. It looks valuable in the bid request, but it misrepresents the underlying supply, distorts performance signals, and complicates measurement and reporting.