The mobile, desktop split may have stabilized at roughly 60% – 40%

According to the IAB’s annual Internet Advertising Revenue report, released last week, the split between mobile and desktop revenue was roughly 65% to 35% in favor of mobile. Ad spending on the desktop is flat, while mobile (and video) are driving significant growth.

Note: This story has been corrected below after an error was detected by Hitwise and the data updated.

Mobile volumes, ad-revenue breakdown directionally aligned

Whether a coincidence or a rational response to analytics, the revenue split corresponds roughly to the distribution of (search) traffic according to new data from Hitwise. At its core, mobile ad revenue growth has been driven by three factors: direction and product emphasis from Google and Facebook, as well as consumer adoption of mobile as a primary search and shopping tool.

Google has said for multiple quarters that its growth is coming from mobile search and YouTube. According to the IAB report, mobile ad spending grew 40% year over year, while desktop spending is flat or down. Combined PC and mobile search accounted for 45% of total ad spending, while search was 43% of total mobile ad revenue.

Mobile search volumes stable

In 2015, Google announced that mobile search had crossed the 50% threshold in multiple countries. The company hasn’t updated that number. In fact, it reiterated the figure at Google Marketing Live this past week.

In 2016, Hitwise released data that suggested mobile search (including tablets) in the U.S. had reached roughly 58 percent of overall search queries. That was based on a comparison of search volume in 11 key categories. I asked Hitwise to update that analysis this month.

Across ten verticals, Hitwise found an average of 58.5% of searches happened on mobile devices. (The original data provided by Hitwise indicated mobile search share was 61.3% on average.) In the aggregate, mobile’s share of search is effectively unchanged from two years ago. And several verticals have seen a decline in mobile search share.

Food was the highest volume category with 68% mobile queries, down from 72% in 2016. Retail saw the lowest percentage of mobile queries (47%), which was down from 56% in 2016. Automotive was 62% mobile in 2016 and 65% in 2019. Other categories were also flat or down.

Is a mobile-SEM slowdown ahead?

While mobile traffic volumes have grown, mobile search volumes appear unchanged overall in the past two years. This suggests some sort of general homeostasis may now exist. Mobile search ad spending was roughly 62% of the total search spend, again corresponding to the query and traffic split between desktop and mobile.

All this says nothing about overall media engagement or time spent, which is dominated by a small number of mobile apps and may continue to drive growth. But it does suggest that mobile search spending could slow in the coming quarters.