The most effective online ad format is the ‘sidekick’, according to research reported by MediaMind, which details the top five most effective digital ad units.

The research found that the sidekick – a sidebar ad that pushes the complete page content to the left on mouseover to make room for an enlarged rich media message – delivers a 60% higher dwell rate than a polite banner ad.

Larger ads that occupy a bigger portion of the screen and use high quality images and video delivered exponentially greater brand awareness, favourability scores and purchase intent, according to the report.

The second-most effective ad format was found to be the ‘pushdown banner’, which users were 164% more likely to engage with than a standard banner.

The research, conducted via an analysis of 30,000 campaigns, named homepage takeovers, messenger ads and video extenders as the other top five most effective formats.

Head of digital brand initiatives at the Interactive Advertising Bureau, Peter Minnium, says the new formats are finally allowing marketers to take advantage of digital media’s ability to engage with web users.

“Creatives and brand marketers have been longing for digital display ad formats that allow them to take full advantage of interactive’s rich canvas,” Minnium says.