The Google-owned video content site YouTube is primed for a 50% surge in advertising revenue by the end of 2013, according to eMarketer. Acquired by search and tech giant Google in 2006 for $1.65bn, YouTube has more than one billion viewers every month and attracts about 20% of all advertising spending on US online video, with 80% of traffic coming from outside the U.S.

Combined revenues from American tech giants Google and Facebook will account for almost HALF of the £6 billion spent on digital advertising in the UK in 2013, according to eMarketer.

Media investment giant GroupM has predicted that UK mobile advertising expenditure is set to rocket in 2014, encompassing one quarter of total ad-spend and one fifth of paid search.

Figures released this week by eMarketer suggest the advertising spend on mobile in the UK has grown 90% over the last year to £999m. Industry magazine The Drum interviews marketing leaders to gather their thoughts on the dramatic upswing.