NEW YORK: Publishers have more than doubled their engagement rate on Instagram, but only a minority are currently active on this platform, research has revealed.

Shareablee, a provider of social media insights, reported that social activity within the media publishing industry had grown 68% in the first half of 2015, with by far the greatest growth coming at Instagram, which registered a 133% increase.

It added, however, that only 41% of media publishers currently have an Instagram presence, "indicating a massive missed outlet for further reach and engagement among social audiences".

"With 300m active users, Instagram is a 'must' for brands to engage," Marci Troutman, CEO of mobile solutions business SiteMinis, told Mobile Marketer.

"Social media is the new billboard for all facets of marketing and advertising and if ignored will be to the detriment of the brands longevity in the future."

Shareablee identified "social amplification" – the sum of shares and retweets on Twitter and Facebook – as a metric for identifying the content that resonates with a social audience. And it said that for the US media publishing industry, this had grown by 105% during the first half of 2015 compared with a year earlier.

Social actions on video content were growing especially fast, up 255% over this period. But the increased engagement was especially evident on Instagram, where Shareablee reported growth of 622%.

This would suggest more opportunities for video advertising, but think tank L2 has observed that Instagram possesses unique limitations in this regard.

Videos on the site have to be 15 seconds or less and usually auto-play without sound, meaning that the platform is "ideal for brief, highly visual content that blends with its creative aesthetic".

In the first quarter of 2015, photos were also getting 1.4 times more engagement than video posts. "Brands with creative shortcomings might be better served moving to other platforms," L2 thus suggested.

Data sourced from Shareablee, Mobile Marketer, L2; additional content by Warc staff