Although connected TV still dominates in share of advertising impressions by device, some digital video ad impressions have shifted to desktop and mobile app usage -- partly due to more at-home video U.S. digital media work and leisure usage.

Extreme Reach, a TV and video advertising-technology company, says video on desktop is at a 23% share for fourth-quarter 2020, up from a 16% share in the same period for 2019. That’s a 37% hike.

Mobile app ad impressions are at a 24% share, dipping from a 26% share in the second and third quarter of 2020.

Connected TV (CTV) device usage still leads with a 35% share, but has dropped from a 47% share in fourth-quarter 2019 -- a 26% decline year-over-year.

Another change is the growing strength in the quarter among media aggregators -- ad networks, DSPs or agency trade desks. Amazon Fire TV can both a premium publisher and an aggregator depending on how it is bought; Roku is defined a premium publisher.

For the first time, media aggregators in the fourth quarter have a greater share than premium publishers, with a 52% share of advertising impressions to 48% share.

For the year overall, premium publishers still command the top share of ad impressions to aggregators -- at 58% to 42%.

Extreme Reach analysis points to aggregators' growth as a result of fewer fraud issues. The fraud rate for aggregators -- the total general invalid traffic filtered rate -- was at 2% in fourth-quarter 2020, down from 4.3% in third-quarter 2020.

Average completion of advertising messages remains high -- slightly down to 80% for all of 2020, from 89% in 2019.

Thirty-second advertising messages still dominate other messaging lengths -- at 79% of all campaigns through Extreme Reach, with 20% for 15-second spots and 1% for six-second advertising.