US advertisers spent a record $49.5 billion on digital advertising in the first half (H1) of 2018, according to the latest data from PwC and the Interactive Advertising Bureau (IAB) appearing in the Internet Advertising Revenue Report. Surprising no one, mobile continues to spend more on mobile marketing but audio is proving to be a strong platform for growth.

The survey includes data concerning online advertising revenues from websites, commercial online services, free email providers, and all other companies selling online advertising.

Specifically, digital advertising in the US rose 23 percent in H1 2018 compared to $40.3 billion in H1 2017.

The report found that marketers are focusing their efforts—and budgets—on mobile, video, social media and audio while backing away from desktop and performance-based revenue pricing models.

Digital audio advertising revenue grew 31 percent in H1 to reach $935 million and nearly two percent of total digital revenue in the US. This includes podcast marketing, which is proving to be a lucrative new frontier for consumer engagement.

Public Media Marketing president David Raphael is on the IAB Audio Committee, which was formed to establish a standardized metric for downloads.

“[Podcasts are] different from any other form of media,” Raphael told AList in a previous interview. “Each listener is a program director. They get to take their devices and decide what they’re going to listen to. They’ve made the choice to listen to something, and that’s an experience that delivers different results for advertisers than from the TV or radio world.”

It’s clear that the marketing industry is starting to realize this, as are the brands that sell advertising. In fact, Pandora unveiled a new podcast format in beta on Tuesday and Oath recently debuted new programmatic audio ad inventory.

Meanwhile, digital video advertising revenue reached $7 billion in the first half of the year, up 35 percent from a year ago. A majority of this revenue (60 percent) is attributed to mobile video, specifically.

At $30.9 billion, mobile advertising is the Internet’s leading platform. It accounted for nearly two-thirds of all digital ad revenue, compared to 54 percent in the first half of 2017. Desktop search was flat at $9.3 billion, but mobile search advertising grew 37 percent YoY to $13.5 billion. Mobile display also grew in H1 to $11.7 billion, accounting for 74 percent of all display ad revenue.

Revenue pricing models changed slightly compared to the same period last year. Impression-based models were slightly more popular, while performance-based models were less so. Hybrid models grew significantly in popularity, however. They increased from $691 million in H1 2017 to an impressive $2.3 billion in H1 2018, accounting for nearly five percent of revenue models.