European social media marketing spend will reach €4.3 billion by 2019, up from €2.6 billion this year — a 10.5% compound annual growth rate (CAGR). This is according to Forrester’s latest five-year social media marketing forecast for the 17 Western European countries.

Across the region, social marketing spend is being driven by consumers’ increased mobile usage, with social mobile advertising growing at a 20% CAGR over the next five years. By 2019, approximately €3,540 million — 82% of total spend — will be delivered through mobile, while only €772 million (18%) will come from desktop. This shift is most obvious in the UK and Germany, where Forrester forecast social media spend on desktop to fall at a compounded annual rate of -17.9% and -14.4%, respectively, through 2019.

Facebook continues to dominate European consumers’ social habits, with an 8% increase in engagement since 2012. Twitter lags behind Facebook, with only 14% of EU-7 online adults visiting the social site at least monthly, compared to Facebook’s 60%. But recent changes to Twitter’s advertising platform and its geotargeting offering will help it to become a media force to be reckoned with in Europe over the next few years.

Read the new research report here.