For years, the Google, Meta, and Amazon triopoly has dominated media budgets, each reigning supreme in its respective category. But cracks are forming in this once impenetrable structure. The rise of AI-integrated search engines such as ChatGPT, Gemini, and Perplexity is fundamentally altering how consumers search, shop, and connect. Meanwhile, platforms like Reddit and Threads are gaining traction, challenging the status quo of traditional social media. At the same time, creators are becoming central to marketing strategies, influencing budget allocations and reshaping how brands engage audiences.

These shifts signal a broader decentralization of media power away from the “OG” walled gardens. As a result, the media and advertising landscape is entering a transformative phase. After years of dominance by a few major players and predictable strategies, 2026 will usher in a wave of disruption driven by generative AI, shifts in consumer behavior, and the maturation of the creator economy. Advertisers are ready to take advantage: According to Forrester’s Q3 2025 CMO Pulse Survey, 86% of US B2C marketing executives plan to experiment with new channels and tactics in 2026, and 83% intend to diversify their media mix beyond the big three. A few of Forrester’s predictions for the 2026 media and advertising space include:

  • Agentic commerce’s popularity will reduce retail media ad sales by 20%. Generative AI-powered search engines such as ChatGPT, Gemini, and Perplexity will become transactional platforms. Consumers won’t just search; they’ll start buying directly within these engines. As fewer shoppers visit traditional retailer websites and apps, retail media networks lose their ability to serve ads effectively. Meanwhile, engines like ChatGPT will evolve into full-fledged commerce media networks, where consumers discover, evaluate, and commit to purchases. To stay visible, brands must rethink their search marketing strategies and optimize for cognitive and commerce search across these emerging platforms.
  • Google’s restructuring will drive a 25% surge in adtech M&A activity. The US Department of Justice is intensifying its scrutiny of Google’s adtech monopoly, and the consequences will be seismic. A forced restructuring of Google Ad Manager — including the divestment of its ad exchange — will fundamentally alter the adtech landscape. This will create space for smaller vendors to compete with a leaner Google, sparking a surge in mergers and acquisitions. Forrester predicts more than 100 M&A transactions in 2026 as vendors and private-equity firms race to reclaim market share. Marketers should evaluate their current adtech spend and consider reallocating budgets to test new or revitalized vendors that emerge from this reshuffling.
  • Creator-led affiliate marketing budgets will double. The creator economy is no longer niche. It’s a core part of the marketing mix, and creator-led affiliate marketing is booming as brands seek scalable ways to drive sales. Companies like Amazon and Walmart now run creator programs that include tens of thousands of influencers monetizing their audiences with affiliate links. What held back creator-led affiliate programs in the past — lack of infrastructure — is now being solved with integrations between affiliate networks and creator marketing platforms such as CreatorIQ. Brands should take advantage of these new integrations and bridge the gap between affiliate and creator marketing teams to build a unified, creator-led affiliate strategy.

Forrester clients can read our full Predictions 2026: Media And Advertising report to get more detail about each of these predictions, plus two more bonus predictions. Set up a Forrester guidance session to discuss these predictions or plan out your 2026 media and communications strategy.

If you’re not yet a Forrester client, download our complimentary guide with a selection of our predictions for B2C marketing, customer experience, and digital business leaders. Also sign up for our public webinar on Tuesday, January 13, 2026, from 1–2 p.m. EST.