LONDON: Global spend on social advertising grew by 114% year-on-year in Q2 2015, more than twice the rate from a year ago, a new industry report has revealed.

This was one of the headline findings in the Kenshoo Digital Marketing Snapshot study, which tracked the 550bn impressions, 9.5bn clicks and $5.5bn in advertiser spend put through the marketing software firm's suite.

Mobile was the key driver of growth with adspend on smartphones and tablets rising 167% year-on-year to account for nearly two-thirds (63%) of all paid social spend, up from 51% last year.

Mobile also accounted for 38% of paid search spending, up from 31% last year, and the report said that the year-on-year increase in paid search spending was fuelled entirely by phone and tablet spending, which rose 71% and 4% respectively.

"Both paid search and social are showing healthy increases in spend and clicks with social obviously showing the much faster growth as it's a far younger market," said Rob Coyne, Kenshoo's managing director for EMEA.

"Existing social advertisers are ramping up spend and getting better results in terms of click volumes despite fewer available impressions, while new social advertisers are also entering the market.

"Mobile has been the key driver of growth in both search and social, with 36% of revenue from advertiser sales now coming from mobile phones, up from 16% last year."

Total clicks from social advertising increased by 129% over the year on top of 64% fewer impressions, leading the report to suggest that marketers are becoming savvy at driving clicks on social ads.

Social advertisers also saw a huge 535% rise in click-through rate (CTR) over the year as they took advantage of changes in the structure and available inventory of paid social publishers.

Data sourced from Kenshoo; additional content by Warc staff