• by Laurie Sullivan , Staff Writer @lauriesullivan, November 13, 2018

Mobile search advertising grew to $13.5 billion -- up 37% in the first half -- while desktop search was flat at $9.3 billion, according to data released Tuesday.

The increase in mobile ecommerce and search contributed to U.S. digital advertising revenue reaching a record $49.5 billion for the first six months of 2018 -- the most advertisers have ever spent on digital media in a first half of a year, reports the IAB.

The IAB Internet Advertising Revenue Report released by the IAB and produced by PwC US reports that the numbers represent a 23% year-over-year increase from the $40.3 billion released for the same period in 2017. 

"At $49.5 billion in total ad revenue for the [first] half [of the year], it’s safe to say digital advertising should exceed $100 billion for the year [in the U.S.]," Brian Wieser, analyst at Pivotal Research, wrote in a note published shortly after the announcement. The analysis attributes the growth to mobile commerce, but overall, search also grew 19% to $22.8 billion in the first half of the year.

Mobile search now accounts for 59% of total search revenue. Mobile display ad revenue, which accounted for 74% of all display ad revenue, grew 45% to $11.7 billion in the first half of the year.

Advertisers, however, spent $30.9 billion on mobile advertising in the first half of 2018, up 42% from $21.8 billion over the same period last year. It now accounts for two-thirds of all digital ad revenue. “76% of the revenue is being generated by the top 10 companies, said David Silverman, Partner, PwC U.S., during an online presentation.

Silverman said only four of those top 10 companies from 10 years ago would be in the top 10 now -- partially due to innovation and merger and acquisitions.

Social media revenue rose 38% to $13.1 billion in the first half.

Video also showed continued growth -- rising 35% to $7 billion -- while mobile video rose 61% to $4.2 billion in the first half of 2018.

Fledgling digital audio advertising grew 31% to reach $935 million in revenue in the first half of 2018 -- on track to exceed last year's full-year revenue of $1.8 billion.