Advertisers spent a record £3.98 billion on digital advertising in the first half of 2015 - up 13.4% year-on-year - according to the latest Internet Advertising Bureau UK Digital Adspend report, conducted by PwC. Display advertising revenues grew at more than twice the overall digital rate (27.5%) to hit £1.31 billion - 33% of total digital adspend, its largest-ever share. Within display, video adspend grew 56% to £292 million (22% share); social media spend rose 51% to £574