David Steinberg's Zeta Global could pursue further acquisitions, according to ad industry analysts and insiders. Astrida Valigorsky/Getty Images

It's shopping season in the advertising industry, and I'm not just talking about the holidays.

After a somewhat sleepy period, the M&A market is stirring back to life, with strategic buyers loading up their carts.

In the past couple of weeks alone, Publicis Groupe completed its $2.2 billion acquisition of the data company LiveRamp ; Salesforce announced a $5.7 billion deal for the customer-engagement platform Braze; India-based Affle said it's buying fellow adtech firm Perion for $420 million; and advertising holding company Stagwell picked up Freestar, a platform that helps publishers sell their ad space.

Jay MacDonald, CEO of the investment bank Digital Capital Advisors, has a simple rule for predicting where M&A could strike next: follow the ad dollars. He pointed to areas including influencer marketing, retail media, and connected TV.…