That’s led marketers to commission agencies like Havas, Dentsu and Kepler to overhaul their organic search approach – 57% of marketers have altered their search strategies since AI Overviews launched in 2024, per a survey by agency NP Digital – while leaving the paid media portion of their search strategy untouched. That status quo won’t hold for long.

Google is ratcheting up its deployment of AI Overviews, with the feature now appearing on 47% of search result pages, according to DemandSphere. Most of those represent the kinds of search queries brands don’t often bid against, broad research queries that imply a web user is situated higher in the sales funnel, but media buyers suspect they won’t be limited for long.

Meanwhile, usage of ChatGPT and Perplexity for search continues to climb. ChatGPT’s active user base reached 400 million at the start of this year while Perplexity added 2 million active users to reach 22 million total between October and the first half of 2025, per Business of Apps. Perplexity is currently toying with its ad product, while ChatGPT is expected to launch its own in the near future.

Dashboard lights

With those silhouettes on the horizon, media buyers are keeping a close eye on a range of indicators.

“I’ve never looked at referral traffic so much in my life,” said Eric Hoover, SEO director at Kepler. He noted referrals have taken on an outsized importance as a key indicator that web visitors are arriving from an AI-generated summary.

The volume, prominence and tone of citations in AI summaries are worth watching, too. “The new ranking signal is the number of citations … it’s a really strong signal of good brand presence,” Hoover explained.

Search practitioners are also keeping a close eye on the cost-per-click (CPC) rates of Google’s search ad inventory. CPCs increased 9% during the second quarter of the year, according to Tinuiti. The metric reflects changing supply and demand dynamics – some of which are due to AI search user behavior, and some to Google’s own tinkering with the landscape of search results pages.

Because AI Overviews appear at the top of results pages, they’ve pushed paid ads that do appear alongside them further down search results pages. Marketers have prioritized spending on keywords less likely to generate an AI summary, driving up CPCs. “Everyone’s chasing the same queries now, and it’s becoming really competitive,” said Jeff Eisenfeld, director of search at Media by Mother.

“We’re seeing that AI Overviews are reshaping search behavior and, in many cases, driving up CPCs as advertisers compete for fewer clicks,” agreed Brooke Hess, vp paid media at NP Digital, in an email.

But AI Overviews aren’t the only culprit. Today’s SERP is a crowded window panel rather than a blue-link directory; visual search results and suggested-search features carry blame as well. “It’s hard to pinpoint attribution,” said Daniel Toplitt, evp, search and digital experience at IPG’s Kinesso performance marketing unit.

And Amazon’s recent, abrupt withdrawal from investment on Google Shopping ads has further complicated the situation. Price fluctuations might be consequences of the e-commerce giant’s retreat, or evidence that brands at large are changing their spending in response to AI search.

“The working thesis is that falling organic and paid search clicks, prompted by increased zero-click behavior, are exerting upward pressure on CPCs,” added Hess. “That said, other factors like increased advertiser competition, seasonal trends, or strategic bidding shifts could also play significant roles.”

Short-term spending and long-term implications

For the most part, overall spending on paid search has held steady. “If [they] see the opportunity to capture more revenue then they’ll be willing to spend more, of course. [But] I don’t think any client has come to use [for an] increase because of AI Overviews,” said Kenneth Yau, paid search managing partner at Dentsu. But a short-term playbook has emerged for those brands that have taken a hit to web traffic – often those in the e-commerce category. They’re increasing paid spend on brand and non-brand keywords as a means of “protecting” the searches that matter most for sales conversions.

“We sometimes recommend increasing paid media investment in the short term to protect visibility as AI-driven search limits organic reach,” said Rachel Klein, svp of owned-and-earned media at Wpromote. But it’s a short-term pivot, a “band-aid” that might prove less effective should (well, when) AI Overviews begin appearing on ever-more search results. 

“Long-term success in AI search (and search in general) depends on a holistic strategy that requires a focus on building authority, not exchanging organic tactics for paid,” she warned. Brands can’t ignore the “foundational” work required to meet the zero-click challenge for long.

That foundational work might well require rethinking what, from an advertiser’s perspective, search is actually for. 

“Zero-click search is affecting search. It’s affecting PR, it’s affecting commerce,” noted Michael Sondak, svp, and head of search for Omnicom Media Group North America.

As such, a response to the zero-click challenge might require a response joining the dots from each of those quarters – one that reflects a brand’s overarching strategic aims, not just the need to drive web users farther down the sales funnel.

“I am less concerned about a CPC increase. The question that I ask my teams from a paid media perspective is: are you having any challenges hitting the business objectives that we’ve signed up to deliver?” said Sondak. “If we’ve signed up for ROAS [or] leads, are we delivering that? That’s the more important metric for me.”