NEW YORK: Privacy and slow download speeds have been cited as reasons for ad blocking but a new survey lays the blame squarely on intrusive ad formats.

Teads, the video ad tech company, surveyed over 9,000 respondents globally, including active ad blockers on desktop/laptop, active ad blockers on mobile, and respondents aware of blockers but who have not yet installed them.

Three quarters of US respondents said that intrusive ads were the largest motivator for installing ad blockers.

The most annoying were, unsurprisingly, pop-ups, with 88% of respondents using ad blockers citing these as the reason for installing the software.

Pre-rolls were also unpopular: 52% of respondents who had installed ad blockers rated these as the most intrusive video format.

But 80% would reconsider installing ad blockers if the ad experience provided them with the choice to skip or close the ad.

"People around the world have expressed an aversion to intrusive ad formats but providing people choice is a global solution," said Rebecca Mahony, CMO at Teads.

But it is the US which appears to have the greatest antipathy to such advertising: 74% of respondents there agreed that intrusive advertising was the top motivation for blocking ads, but that fell to 60% in Italy.

And within the US blocking community there were some distinct demographic differences. On mobile, for example, blockers were 22% more likely to be male than non-blockers; and they were also 78% more likely to be Hispanic than non-blockers.

A significant proportion of those installing ad blockers had heard about them from friends (44%), while word of mouth (26%) and social media (18%) also featured.

IAB President Randall Rothenberg launched an outspoken attack on ad blocking in his opening speech at this week's IAB Annual Leadership Meeting in Palm Desert, California. (For more, read Warc's exclusive report: Rothenberg pummels ad blockers.)

He described AdBlock Plus, in particular, as "an old-fashioned extortion racket, gussied up in the flowery but false language of contemporary consumerism".

He went on to condemn "ad-block profiteers" as "rich and self-righteous, who want to tell everyone else what they can and cannot read and watch and hear – self-proclaimed libertarians whose liberty involves denying freedom to everyone else".

Data sourced from Teads, IAB; additional content by Warc staff