The growing market for social and search spending is positive for companies like Facebook and Google, the “duopoly” that for years has seen double-digit growth in ad spending. Google’s parent company Alphabet reported a 16% increase in ad sales in Q2 from a year earlier, which was respectable for a mature company that’s grown with the broader digital ad market.

The growth rate of social media companies varies by company, with younger platforms tending to show the fastest increases in ad revenue. This year, the industry has seen ad revenue gains of 62% for Pinterest, 48% for Snap, 28% for Facebook and 21% for Twitter. TikTok, the social video app created by Chinese tech giant ByteDance, doesn’t disclose its ad sales, but is emerging as a disruptive force as the startup builds out its marketing platform and brands explore how to best advertise on the nascent channel.

Meanwhile, Amazon has proven to have a budding ad sales business that grew 37% in Q2 from a year earlier, making the e-commerce giant the third-biggest digital platform for advertising behind Google and Facebook.